Home

DACCF Utilities Installation Guide and User Manual

1. G 3 Logical Drives edis meu A MN RE G 4 Mirroring 00 nUr pace e REESE Ple reri ie ee ees G 4 Pack ois RIA RB eennc3 e eee uude XUI wg ae tema ges eod ER G 4 Parity edet aep e tS E eet AA eG are pd em de PRA G 4 RAID coe annee gants DUAE d bie pid ND ER CHE IT G 4 RAID Eevels outre hades oS av ees EE ER Cni P NEAR IER G 5 Replacement Table G 5 Rotated XOR Redundancy G 5 SIeR BDIT NC cite NDA ea G 6 SCSI Drive States ise at d G 6 Segment SIZe 4e ise pee dette e a dass ete s G 7 SESSION etu on Rx UR REQUUERI CERAM EMPIRE RP ONE CAS G 7 Standard Disk Drive cele oy ob lm orla A es G 7 Standby Replacement of Disks Hot Spare G 7 Stripe Order a0 eoa tetto repr xs dub ene pu d Mea G 9 Stripe SiZe Hi edel eee uere D UI ee EPPEN RES G 9 Stripe Width rt oS a Ac ueber de ANIME UR G 9 SNIPING eb ERTG ors eel uus eA NO OR ue ee O G 9 Syst m Drives 52258 e ee peer e dor VERO D pw BRA A Ed G 9 TargetID oe id A peer iae or EX eee i By G 9 Write Back Cache sos cesse x nexu ip alae mem ror eR RES BRE RT G 10 Write Through Cache G 10 Chapter 1 Introduction to DACCF MYLEX Disk Array Controller Configuration Utility Version n nmn mmddyy n Channel nn Target DACIGBXX tn Firmware version n m Hain Menu BZ New Confi
2. 2 8 Assigning RAID Levels to System Drives 2 9 Matching RAID Levels to Available Drives 2 9 Applying the CAP Strategies 2 10 Configuring for Maximum Capacity 2 11 Configuring for Maximum Availability 2 12 Impact of Controller Cache on Availability 2 12 RAID Levels and Availability 2 14 Configuring for Maximum Performance 2 15 RAID RUIGS 5 x eret Ere RR Ee aite edt e p d eo yc TE eden 2 16 CAP Strategy Questionnaire 2 17 Using the Array Configuration Tables 2 17 Key Points About the Tables 2 18 Chapter 3 Preparing the Array OVOIVIOW A MEDIE ad A E PCR DU NEP 3 1 Navigating within DACCF 3 2 DACCF Screen Regions and Objects 3 2 Title Window e yir PIRE P EPUM EV Seles uer een 3 2 Actions Bal t e vue x rene mic M nt NS MD 3 2 Menus and Dialog Boxes 3 2 Device Representations 3 3 Help BOX ce flexu vx Au M UU PEE ED ETE ER 3 3 Getting Around Within DACCF 3 3 Cursor Keys and Jump Keys
3. A 1 SCSI to SCSI DAC960 Products A 1 Appendix B Frequently Asked Questions Appendix C Command Line Arguments Appendix D DACCF Error Conditions NVRAM Flash Configuration Mismatch D 1 Installation Abort o ess rc a y ci D 1 Configuration Checksum Error D 3 Errors Which Cause a Drive to be Killed D 3 SCSI Sequence Error D 3 SCSI Busy Status cri ae mt Ro piu a a do D 3 Timeout on a Command D 3 Media Error Recovery Flow D 4 Interrogation Sequence Start Drive D 4 Operator Command D 4 viii Glossary Bad Block Table or Bad Data Table G 1 Cache sara dure te a to G 1 Gache Flush 225 pu eng oes Rennes we me de tin pes G 1 Cache line Size iu breues IA G 1 Chann lis emu ute DPI TEMA eL PR EIN FCRIPTIS G 1 Consistency Check xeu date Pere dns ET e EDEN E G 1 Disk Failure Detection G 2 Disk Media Error Management G 2 Drive Groups or Drive Packs G 2 Hot Replacement of Disks Hot Swap G 3 Logical Drive States
4. Choose VES to Format N or lt ESC to Previous Menu Figure 3 1 DACCF Screen Areas and Objects Title Window Throughout DACCF a title window on the top of the screen will display the utility title version number and date MYLEX Disk Array Controller Con figuration Utility Version n nn mm dd yy In addition the currently selected controller s name slot number and firmware version are displayed n Channel nn Target DAC960XX n Firmware version n nn Actions Bar Each screen uses the bottom row of the display to indicate allowed operator actions Menus and Dialog Boxes Each screen has either a menu of items that can be selected or a dialog box requiring a specific action 3 2 DACCF Utilities Preparing the Array Device Representations At certain points in DACCE a representation of a particular device a disk array for example will be displayed along with a menu and or dialog box Often DACCF permits you to navigate within the device to select specific objects a disk drive for example upon which to perform specific opera tions Navigation is normally performed via cursor keys or via a mouse as outlined below Help Box At key points throughout DACCF a help box is displayed when a specific menu choice is highlighted The Help box usually contains a textual descrip tion of the functions of the menu item Help boxes are also displayed at stra tegic points throughout the program to inform you of acti
5. RAID RAID stands for Redundant Array of Independent Disks The DAC960 Series controllers implement this technology to connect up to 7 SCSI devices simultaneously on each channel for firmware versions below 3 0 and up to 15 SCSI devices per channel for firmware 3 0 and above Several different forms of RAID implementation have been defined Each form is usually referred to as a RAID level All the RAID levels supported by DAC960 Series controllers are shown below The appropriate RAID level for a system is selected by the system manager or integrator This decision will be based on which of the following are to be emphasized Disk Capacity Data Availability redundancy or fault tolerance Disk Performance G 4 DACCF Utilities Glossary RAID Levels Level 0 Block striping across multiple drives is provided yielding higher performance than is possible with individual drives This level does not pro vide any redundancy Level 1 Drives are paired and mirrored All data is 100 duplicated on a drive of equivalent size Level 5 Data is striped across several physical drives For data redun dancy drives are encoded with rotated XOR redundancy Level 0 1 Combines RAID 0 striping and RAID 1 mirroring This level provides redundancy through mirroring Mylex RAID 6 JBOD Sometimes referred to as Just a Bunch of Drives Each drive is operated independently like a normal disk controller or drives may be
6. Carr Ei 1 uz Dru Figure 4 14 Consistency Check 3 Use the cursor keys to select a particular redundant system drive to be checked for consistency Manual No 771953 4 13 Administering the Array Note Selecting a non redundant system drive for a consis tency check will result in an error message as such drives cannot be checked in this manner 4 Press ESC to return to the Consistency Check menu Figure 4 15 MYLEX Disk Array Controller Configuration Utility Version n nmn nn dd uy n Channel nn Target DACI6GBXX tn Firmware version n m Consistencu Check 1 Select Susten Drive 2 Start Check Choose this option to check consistency of selected System drive Figure 4 15 Return to the Consistency Check Menu 5 Select Start Initialize from the Consistency Check menu 4 14 DACCF Utilities Administering the Array 6 A confirmation box will appear asking if you want to automatically restore consistency to the drive Figure 4 16 MYLEX Disk Array Controller Configuration Utility Version n nn nn dd uy n Channel nn Target DACIGBXX iin Firmware version n m Consistency Check I cg Sus Dre H Do you want to enable automatic restoration 7 YES Figure 4 16 Automatic Restoration of Consistency to Drive Select YES to restore consistency to the selected system drive Be aware that potential dat
7. 3 3 Selecting an Item 3 4 Exiting a Menu uere RUPEE Ee REY Hep PUE 3 4 Using a MOUSe ics oe eR A ex xor PR Roc RUR rate 3 4 Starting DAGGE iius hae Phen re ep RE puede oio 3 5 Command Line Parameters 3 5 Opening Screens sis nu ROS PR a a 3 5 Probl ms pep ete Dye es ep nio dran S i ie Ring 3 6 Select DAGO9060 ripe dette Dues d OVER bns Bon war edid ad dob aes 3 7 Set Controller Parameters for Your Application 3 8 SUIS ZE x xo ERES ER UD EE ER UE S RENE pd fos 3 8 Segment Size ui ge RA due e e e serio eser ee eee d vate 3 9 Low Level Format the Drives 3 10 Procedure coru EVE HEUS HDI SN Db DIS MR E 3 10 vi Create the Drive Groups 3 15 Automatic Configuration 3 15 Automatic Configuration Procedure 3 15 New Configuration 3 20 Define Drive Groups 3 20 Change or Cancel a Drive Group 3 24 Create a Standby or Hot Spare disk 3 25 Arrange the Drive Groups 3 25 Device Information 3 26 Defining and Creating a System Drive 3 27 Creating a System Driv
8. Mylex authorized reseller or Mylex marketing representative Mylex is a registered trademark of Mylex Corporation DAC960 is a trademark of Mylex Corporation Microsoft and MS DOS are registered trademarks of Microsoft Corporation Windows and Windows NT are trademarks of Microsoft Corporation Novell and NetWare are registered trademarks of Novell Inc Unless otherwise noted companies names and data used in examples herein are fictitious About this Manual This manual covers the steps involved to install and use the Mylex Disk Array Controller Configuration Utilities DACCF software This manual is divided into a number of sections presented in the order in which they are needed over the life of your disk array Introduction to DACCF provides a brief introduction to the Disk Array Controller Configuration Utilities Here you ll find a description of the software the functions it provides when it can and should be used and the environment needed for using the utilities Configuration Strategies presents some scenarios and suggestions for configuring your array for optimal performance Look here for informa tion on how the DAC960 implements RAID technology and for tips on making your array perform well in your specific application Preparing the Array covers array hardware preparation configuration and initialization After completing the steps in this section you can install the operating system for your specific environm
9. Sys Dry Size MB RAID Write Mode 6 658 5 WRITE BACK 1 1813 1 WRITE THRU Figure 4 6 Saving the Updated Configuration Select YES in the dialog box to save the configuration and you will return to the Main menu Select NO to discard all changes made to drive groups group arrangements system drives and write policy and you will return to the Main menu or Press the ESC key to cancel the save process and return to the System Drive Definition menu Any changes are retained and additional modifications can be made However the configuration will need to be saved before proceeding to the last step of array preparation Manual No 771953 4 7 Administering the Array Rebuild Drives If one of the physical drives fails suddenly in an array with redundant system drives RAID level 1 5 or 1 0 and no standby drives the DAC960 system will continue to function without any interruption However during this critical period the DAC960 system can tolerate no further physical drive fail ures as data on the drives is no longer redundant During this period the array is considered to be in a Critical state In order to restore the system s redundancy fault tolerance the failed physical drive needs to be replaced with a functional physical drive of the same size and same SCSI ID and the data needs to be rebuilt on this newly installed physical drive Use the Rebuild option on the Main menu for this purpose Note Normal
10. this could also be the problem To remedy this situation run DACCF DDFC Once the main menu is displayed you can then exit the utility The bit will be set edfc This resets the bit to allow disconnects on first command Manual No 771953 C 1 Command Line Arguments C2 DACCF Utilities Appendix D DACCF Error Conditions NVRAM Flash Configuration Mismatch The DAC960 stores two copies of the array configuration in different mem ories of the controller One copy is stored in Non volatile RAM the other in an Electrically Eraseable Read Only Memory or Flash EEPROM During initialization DACCF compares each copy of the configuration If a differ ence is detected the error message above is displayed To remedy this prob lem 1 Press any key The Load Configuration screen will display 2 Select the source to view either NVRAM or FLASH memory In most cases the information stored in FLASH memory will be more accurate and Mylex recommends that you check that source first 3 Review the configuration from the selected source and decide if this source should be saved to both sources e To save the configuration Press the S key To not save the configuration and to review the other source for a more accurate copy of the configuration follow the directions on the screen Installation Abort The Installation Abort message appears when the configuration informa tion stored in the controlle
11. AT Failed on Device nel 0 Target ID 1 Figure 3 12 Device Error During Format 8 Toreturn to the Main menu from the Tools menu press the ESC key 3 14 DACCF Utilities Preparing the Array Create the Drive Groups After the devices have been formatted the first step in configuration is deciding whether to configure drive groups automatically or manually Automatic configuration has certain limitations see Automatic Configura tion below but is the fastest way to prepare an array for operation Manual configuration gives you complete control of the array s design but will take longer to complete than an automatic configuration Mylex recommends that you read both sections before proceeding to determine which method makes more sense for your installation Note DAC960 Series controllers ship from the factory with no configuration information stored in memory Automatic Configuration The Automatic Configuration option configures the array with just a few keystrokes and can only be used when the array consists of between 3 and 8 drives Although drives of different sizes may be used in the array Auto matic Configuration will only operate upon drives of the same physical size The Automatic Configuration option creates an array with the following properties e All of the physical drives are contained in a single drive group e The drive group is defined as a single RAID level 5 system drive e Hot spare standby dri
12. Controller Configuration Utility Version n nmn nn dd uy n Channel nn Target DACIGBXX iin Firmware version n m Tgt Channel Number ID A 1 Tools NL 6 C Crad 1 Bad Block Table NL 2 Error Counts 1 CA m 17 3 Format Drive BY NL 4 Make Online 221 5 5 Kill Drive NL 6 Backup Restore conf 3 Bal Clear Configuration NE Ll 8 Print Configuration 4 NL 5 males NE The existing config e Ll will be destroyed tt 6 1 EE eee YES Press FZ to View full Display Figure 4 26 Clear Configuration Confirmation Select YES to clear the current configuration You will return to the Tools menu Select NO to abort the clearing of the configuration You will also return to the Tools menu Note All DAC960s are shipped with the configuration cleared 4 24 DACCF Utilities Administering the Array Print Configuration To create a printed copy of the configuration which can be used to configure the array manually follow these steps 1 Select Print Configuration from the Tools menu The output file name box will appear Figure 4 27 MYLEX Disk Array Controller Configuration Utility Version nem nn dd uy n Channel nn Target DACIGBXX tn Firmware version n m Tgt Channel Number ID B 1 Tools INT 4 CA E 1 Bad Block Table NL 2 Error Counts 1 C O i 3 Format Drive BY NL 4 Make Onl
13. Disk Mirroring Mirrored fault tolerance Data is written to one disk and then the same data is written to another disk If either disks fails the other one in the pair is automatically used to store and retrieve the data 5 Striped fault tolerance Data and parity are striped across asetof multiple at least three drives If any of the drives fails the data or parity information from the failed drive is computed from the information from the remaining drives 0 1 Data Mirroring Mirrored and striped fault tolerance Data is striped across multiple drives and written to a mirrored set of drives This arrangement can survive multiple drive failures and continue to operate JBOD Just a Bunch of Disks This configuration offers no redundancy and is not recommended for applications requiring fault tolerance 2 14 DACCF Utilities Configuration Strategies Configuring for Maximum Performance Your array can be optimally configured for the type of application you plan to deploy but you should be aware that an optimal setting for one type of access profile is not optimal for all applications What s the best RAID level for a particular application or environment The relative performance advan tages of each of the RAID levels is presented in Table 2 6 Table 2 6 RAID Levels and Performance RAID Level Access profile characteristics 0 Excellent for all types of I O activity 1 Excellent for write intensive applications 5
14. Excellent for sequential or random reads and sequential writes 0 1 Excellent for write intensive applications JBOD Mimics normal individual disk performance characteristics Manual No 771953 2 15 Configuration Strategies RAID Rules A small but important set of guidelines should be followed when connecting devices and configuring them to work with a DAC960 controller They are 1 2 16 To lessen their impact on the SCSI bus connect SCSI based tape CD ROM and other non disk devices on a single channel which preferably does not service any disk drives If you have more than two disk drives distribute the drives equally among all the channels on the controller This will result in better perfor mance DAC960 Series controllers have between one and five channels depending upon the model A maximum of eight devices can comprise a drive group A drive group can contain devices on any channel Include all drives of the same capacity up to eight total in the same drive group If configuring for a standby or hot spare drive make sure that the standby drive size is greater than or equal to the capacity of the smallest drive in ALL the redundant drive groups When replacing a failed drive make sure that the replacement drive size is greater than or equal to the size of the smallest drive in the affected drive group DACCF Utilities Configuration Strategies CAP Strategy Questionnaire You need to answer the follow
15. Figure 3 25 MYLEX Disk Array Controller Configuration Utility Version n nmn nndd yy n Channel nn Target DACIGBXX iin Firmware version n m n coe pac Pack Definition oc p orne Morse EA 123 PAK DRUS SIZE MB 4 EA Ll A 3 3039 a E TE Press FZ to View full Display Figure 3 25 Arranging the Drive Groups Manual No 771953 3 25 Preparing the Array To arrange a drive group move the highlighted bar to any drive of the desired group and press the Enter key to arrange it The drive group will be added to the table on the lower right side of the screen which lists the drive group s pack identifier the number of drives in the group and the capacity of the drive group This table is called the pack arrangement table Note The drives belonging to unarranged packs drives that are not part of any pack or drives of arranged packs that have not been configured into any system drive will be automatically configured as standby drives If all of the packs are arranged you will return to the New Configuration menu automatically Device Information To obtain information about any physical disk drive connected to the DAC960 Series controller 1 Select Device Information from the Pack Definition menu 2 Using the cursor keys select the device and press Enter The selected drive s information is displayed in the lower right side Figure 3 26 MYL
16. In the illustration above the smaller system drive B can be assigned a RAID 5 level of operation while the larger system drive B might be assigned a RAID 0 1 level of operation Remember that different RAID levels exhibit different performance charac teristics for a particular application or environment DAC960 Series control lers allow for complete versatility in this regard by allowing multiple different RAID levels to be assigned to a drive group Matching RAID Levels to Available Drives You may be asking How many drives do I need for a certain RAID level The table below provides this information DACCF looks at the number of drives in a drive group and presents you with only those RAID levels that have enough drives to support the choices Manual No 771953 2 9 Configuration Strategies Table 2 2 RAID Levels vs Number of Drives Number of Drives RAID Level Minimum Maximum Striped 0 1 Striped 5 The striped 0 1 and striped 5 RAID levels can only be implemented on Super Drive Groups i e spanned drive groups with the same number of drives that have been arranged adjacent to each other Since they are striped these RAID levels can be thought of as RAID level 0 1 0 and level 5 0 respectively Applying the CAP Strategies Capacity Availability and Performance these are the three benefits that all DAC960 RAID solutions have in common The terms collectively known as CAP should characterize you
17. Initialize System Drive uz Dru ll Simultaneous initialization of 8 System Sus Drv 1 drives can he done Using cursor keys move to the required System drive box and hit ENTER to select WARNING Initialization of the System drives WILL destroy data on the drives Figure 3 36 Initialize System Drives Manual No 771953 3 35 Preparing the Array 3 To mark a system drive for initialization highlight a system drive using the cursor keys or mouse and press the Enter key As multiple system drives can be initialized simultaneously repeat this process until the desired system drives again all drives should be initialized are marked with a check mark Figure 3 37 MYLEX Disk Array Controller Configuration Utility Version n nmn nndd yy n Channel nn Target DACI6BXX tn Firmware version n m Initialize System Drive as 1 Sus Dru A Simultaneous initialization of 8 System METE Dru 1 drives can be done Using cursor keys move to the required System drive box and hit lt ENTER gt to select WARNING Initialization of the System drives WILL destroy data on the drives Figure 3 37 All System Drives Selected 4 Press ESC to return to the Initialize System Drive menu Figure 3 38 MYLEX Disk Array Controller Configuration Utility Version nem nm dd yy n Channel nn Target DACI6HXX tn Firmware version n m Initialize System Driv
18. RAID Level selection menu pops up Figure 3 29 Use the cursor keys to select a RAID level appropriate for the drive group The cursor will only move to a valid RAID level allowed by the number of drives in the selected group The number of drives in a drive group is also known as the stripe width of the drive group Press the Enter key to select the RAID level for this system drive Table 3 3 presents the minimum num ber of drives necessary to support each RAID level Manual No 771953 3 29 Preparing the Array Table 3 3 Drives per drive group and supported RAID levels Number of Drives RAID Levels Available 1 Mylex RAID Level 7 also known as JBOD 2 0 1 3 or more 0 5 0 1 also known as RAID Level 6 5 Define the size of this system drive in the Enter Size MB popup Figure 3 30 By default the maximum possible size for the system drive you re defining is displayed To accept the default capacity press the Enter key Toenter a value less than or equal to the default size type the value and press the Enter key MYLEX Disk Array Controller Configuration Utility Version n nn nndd yy n Channel nn Target DACI66XX tn Firmware version n m Pak4 Drvs Size MB System Drive Definition AY 3 3439 1 Create System Drive Z Toggle Write Policy Sus Dru Size MB RAID Write Mode Enter Size MB 3839 Figure 3 30 Ent
19. Screen 4 10 DACCF Utilities Administering the Array 7 At the conclusion of the rebuild a message indicating success will be displayed Figure 4 11 Press any key to return to the Main menu MYLEX Disk Array Controller Configuration Utility Version n nn nn dd uy n Channel nn Target DACIGBXX iin Firmware version n m REBUILD Tgt Channel Number H System Drive B 1BBz BTE a 1 EET 2 CI L 3 rum JL EE EI Co e Co a m d Figure 4 11 Rebuild Complete Note A rebuild fails if read errors are encountered on Manual No 771953 existing physical drives which comprise the system drive The View Rebuild BBT function View Rebuild BBT on page 4 41 reports all such errors Administering the Array Consistency Check A consistency check compares the data and parity information on redundant system drives e g system drives with RAID levels of 1 5 or 0 1 to ensure that they can continue to function in the event of a physical drive fail ure If a difference between the data and its generated parity is detected the consistency check process can resolve the difference Only one system drive may be checked at a time for consistency WARNING Restoring consistency could mean loss of data in the blocks that were found inconsistent resulting in data corruption and or loss of data Use the consistency check with caution To verify and if necessary co
20. Version n nn nn dd uy n Channel nn Target DACIGBXX iin Firmware version n m Tgt Channel Number Pack Definition ID 6 1 123 p a Revie A E 123 PAK DRUS SIZE MB 421 ET Press F2 to View full Display Figure 3 21 Pack Definition Menu Manual No 771953 3 21 Preparing the Array 3 Select Create Pack to begin grouping the drives into a pack The high lighted bar is positioned on the first device found by the controller on the first channel Figure 3 22 MYLEX Disk Array Controller Configuration Utility Version n nmn nn dd uy n Channel nn Target DACI6BXX tn Firmware version n m Tgt Channel Number Pack Definition ID 6 1 RDY 1 Create Pack 6 C C Z Cancel Pack RD Y 3 firrange Pack 123 CA 4 Device Information Rd PAK DRUS SIZE MB 3 C s CA C ra MAAA Figure 3 22 Creating a Drive Group 4 Use the arrow keys to position the highlighted bar on a disk device iden tified as RDY Device identification is shown in Table 3 2 Table 3 2 Device identification and status Device Display Device Status RDY Disk is operational but not currently included in a drive group DED Disk is dead or has been manually taken offline SBY Disk is a hot spare standby drive ONL Disk is operational and is included in a group FMT Disk is being low level formatted WOL Disk is part o
21. displayed Figure 3 33 MYLEX Disk Array Controller Configuration Utility Version n nn nndd yy n Channel nn Target DACIGBXX iin Firmware version n m Pak Drus Size MB SAVE configuration 7 Ar 3 3039 ES NO Sys Dry Size MB RAID Write Mode B 2626 5 WRITE BACK Figure 3 33 Save Configuration Dialog Box Select YES to save the configuration You will return to the Main menu Select NO to discard all changes made to drive groups group arrangements system drives and write policies You will return to the Main menu Press the ESC key to return to the New Configuration menu Figure 3 20 Any changes are retained and additional modifications can be made However the configuration will need to be saved before pro ceeding to the last step of array preparation This completes the configuration process To finish preparing the array initialize the system drives as described in the following section Manual No 771953 3 33 Preparing the Array Initialize the System Drives The last step in the preparation of the array is the initialization of the system drives Mylex recommends that all system drives be initialized immediately after they are created WARNING Failure to initialize a system drive will result in unpredictable drive behavior such as an inability to boot or load the operat ing system or failure of a consistency
22. drives A system drive can be any percentage of a drive group Eight system drives are allowed per controller under firmware versions below 2 6 Under firmware versions at or above 2 6 32 system drives are allowed per controller If different RAID levels are configured for a single drive group then the effective capacity will be different than the value shown in the table due to the fact that the table does not take into consideration the mixing of RAID levels within a drive group DACCF Utilities Configuration Strategies Table 2 7 Array Configuration Strategies Drives amp Drive Groups One Drive A 0 Two drives A 0 B o A 00 Three drives A 0 B o C o A 00 o A 000 Four drives A 0 B C D 0 A gt 000 Manual No 771953 Possible RAID Levels A JBOD A JBOD B JBOD A 0 A 1 A 0 A 1 SBY A 5 A 5 SBY A 0 1 SBY Effective Capacity A 1 Dr N QO OF PR gt gt N gt gt gt HJQ wo E 2 19 Configuration Strategies 2 20 Table 2 7 Array Configuration Strategies Continued Drives amp Drive Groups Five drives O O O O O 0000 00 00 o p pjo 2 gt 2M0 0D gt A 00000 A 000 B 00 Possible Effective RAID Levels Capacity A 5 SBY A 0 A 1 SBY B 0 B 1 SBY DACCF Utilities Configuration Strategies Table 2 7 Array Configuration Strategies Continued Drives Y Drive Groups Six drives D MO
23. fraction of the disk space required by RAID 1 to achieve data redundancy Provides good performance for transaction processing applications because each drive can read and write independently Should a drive fail the controller continues to allow reads and writes by calculating the missing information using the parity data The controller can recreate lost data on a replacement drive without interrupting access by users It can perform the rebuild automatically if a hot spare is available or the system administrator can manually initiate a rebuild Drawbacks Cannot match RAID 0 in write performance because of the processing required to compute and write error correction data While a con troller is rebuilding a drive users will experience reduced performance if they try to read or write data to the array Drives Minimum 3 Maximum 8 2 4 DACCF Utilities Configuration Strategies RAID 0 1 Mirroring and Striping The controller combines the functions of both data striping RAID 0 and disk mirroring RAID 1 Sometimes referred to as Mylex RAID 6 Benefits Optimizes for both fault tolerance and performance Provides excellent performance for all data needs Drawbacks Requires half the available disk space for data redundancy the same as RAID level 1 Drives Minimum 3 Maximum 8 JBOD Single Drive Control Just a Bunch of Drives the controller treats each drive as a stand alone disk and provides a high perform
24. on page 4 7 4 4 DACCF Utilities Administering the Array Create New Standby Drives To assign a new physical disk to standby hot spare status do the following 1 Ensure that the device has been low level formatted then select Define Pack from the View Update Configuration menu 2 Verify that the status of the new device has a status of RDY If the status of a new device is set to UNF the device requires low level formatting as described in the previous chapter Note In large configurations multiple standby drives may be created for an extra level of protection 3 Whenone or more physical disks has a status of RDY press the ESC key to return to the View Update Configuration menu Figure 4 2 4 Pressthe ESC key again DACCF will notice drives available for standby duty and ask if you want to save the configuration Figure 4 5 MYLEX Disk Array Controller Configuration Utility Version n nn mmddyy n Channel nn Target DACIGBXX iin Firmware version n m Pak Drus Size MB SAVE configuration 7 Ar 3 987 B 2 2826 YES O ero Sys Dry Size MB RAID Write Mode 6 658 5 WRITE BACK 1 1813 1 WRITE THRU Figure 4 5 Save Configuration to Create Standby Hot Spare Drives Select YES to save a new configuration and create standby drive s Select NO to avoid creating the standby drive s The current configu ration will be retain
25. or written at one time Under DACCF the segment size also known as cache line size should be based on the stripe size you selected See Table 3 1 in Chapter 3 for the available segment size settings to use for each stripe size The default segment size for Mylex DAC960 controllers is 8K A large segment size 64K is useful when accompanying a 64K stripe size for applications requiring large sequential reads or writes such as video playback from disk However it can actually hinder system performance if files are smaller or if data access is more random than sequential Small seg ment sizes especially 8K are best for most data processing situations Manual No 771953 4 33 Administering the Array Stripe Size The Stripe size function is used to tune the controller performance for a spe cific environment or application Generally stripe size optimization is as fol lows e Smaller stripe sizes provide better performance for random I O e g RAID 5 network file service or OLTP processing e Larger stripe sizes provide better performance for sequential transfers e g RAID 0 RAID 1 0 digital video etc Available stripe sizes are 8K 16K 32K and 64K For firmware versions below 2 6 the default stripe size for Mylex DAC960 Series controllers is 8K For firmware versions at or above 2 6 the default stripe size is 64K WARNING DATA LOSS will occur after changing the stripe size on a controller with existing logical
26. packs A drive group is a collection of one or more physical disk drives Create and configure one or more system drives A system drive has a defined capacity RAID level and write policy Up to eight or 32 system drives can be created for the entire array depend ing on the firmware version Maximum system drive size is 32GB or 2 terabytes also depending on the firmware version Save the configured information After configuring the array save the configuration to the controller Initialize the system drives The final step is to initialize all of the system drives that have been con figured above Once this process is complete the host operating system may be installed and the file system may be created on the array Manual No 771953 3 1 Preparing the Array Navigating within DACCF DACCF Screen Regions and Objects You control DACCF via a text based interface Screen areas and objects that you ll encounter while using DACCF are shown in Figure 3 1 and explained below MYLEX Disk Array Controller Configuration Utility Version n m mm dd yy n Channel nn Target DACI6AXX tn Firmware version n m Tgt Channel Number Tools 1 ONL ga LES 1 Bad Block Table 0 2 Error Counts rr ONL 4 Make Online B uc 5 Kill Drive ONL 6 Backup Restore conf G3 7 Clear Configuration B Print Configuration A11 DATA will be LOST Proceed with Format 7 a YES
27. sure that you have 12V power try changing the EEPROM or the NVRAM I get an error message saying Initialization failed What should I do This condition occurs when a drive is not responding to controller com mands during the initialization process Verify the operation of the individ ual devices using the Tools menu and if necessary replace the malfunctioning drive s I have a hot spare configuration One of my disks failed and the hot spare took over l ve replaced the failed disk but cannot get the con troller to recognize the replacement disk which can now become the hot spare What should I do Follow these steps 1 Disconnect the replacement drive 2 Invoke DACCF 3 Select View Update Configuration from the Main menu 4 Select Define System Drive from the View Update Configuration menu xd Select Toggle Write Policy from the System Drive Definition menu 6 Press the Enter key to change the write policy for the first or any system drive then highlight the same drive and press the Enter key to change it back to its original value 7 Press the ESC key twice 8 Answer YES to save the updated configuration although in effect nothing has been changed B 2 DACCF Utilities Frequently Asked Questions 9 Exit DACCF 10 Connect the replacement drive 11 Invoke DACCF 12 Select View Update Configuration from the Main menu 13 Press the ESC key 14 Answer YES to save the new config
28. the capacity of the array or create new system drives Alternatively you may want to change the write policy for a defined system drive After a power or system failure the data on the array s system drives should be verified and if neces sary repaired This section explains how to accomplish these and other tasks Viewing Updating the Configuration From the Main menu use the View Update Configuration option to view edit or update an existing array configuration Select View Update Configuration from the Main menu to perform any of the associated activities Figure 4 1 MYLEX Disk Array Controller Configuration Utility Version n nn nndd yy n Channel nn Target DACIGBXX iin Firmware version n m Hain Menu Bi Automatic Configuration BZ New Configuration B4 Rebuild BS Initialize System Drive B6 Consistency Check B7 Tools HB Select DAC96H 49 Advanced Functions 18 Diagnostics Choose this option to view edit write policy add additional System drive s add Standby drive s to existing configuration Figure 4 1 View Update Configuration Option Manual No 771953 4 1 Administering the Array The View Update Configuration menu is displayed Figure 4 2 MYLEX Disk Array Controller Configuration Utility Version n nn nm dd yy n Channel nn Target DACI6BXX iin Firmware version n m View Update Configuration 1 De
29. to be replaced An extra existing standby drive may be required elsewhere and therefore need to be removed from the array A new drive may need to be added to the array as a standby or hot spare drive to provide automatic fault tolerance This section describes how to accomplish these and other tasks Tools Many of the functions necessary to ensure continued data availability before during and after a drive is replaced are found in the Tools menu Activate the Tools menu Figure 4 40 by selecting Tools from the Main menu MYLEX Disk Array Controller Configuration Utility Version n nn nn dd uy n Channel nn Target DACIGBXX iin Firmware version n m Hain Menu Bi Automatic Configuration BZ New Configuration H3 View Update Configuration 4 Rebuild BS Initialize System Drive BG Consistency Check 47 Tools HB Select DAC96H B3 Advanced Functions 18 Diagnostics Choose this option to perform special operations like lou level format of physical drive s backup restore print and clear the existing configuration Figure 4 40 Tools Option 4 40 DACCF Utilities Administering the Array Bad Block Table Bad Data Table A bad block is defined as a section on a physical disk which cannot reliably store information Viewing the table to inspect the number and location of bad blocks can be used to troubleshoot a failed rebuild operation or can help predict a phys
30. tools to selectively take drives on line or off line and to rebuild or reconstruct data on a failed drive s replacement In the case of a power loss potential data corruption can occur DACCF can be used after power restoration to perform a consistency check to locate and correct if necessary any data errors on the drives Diagnostic and Configuration Utilities DACCF can run diagnostic routines against the DAC960 controller and to back up restore and print controller configuration data to a disk file Manual No 771953 1 3 Introduction to DACCF DACCF Requirements DACCF has the following requirements for successful execution Hardware Either a stand alone or host based Mylex DAC960 Series controller If the DAC960 Series controller is connected to the computer via a SCSI cable an approved SCSI Host Bus Adapter is necessary An 80386 class or newer CPU A video adapter any type A floppy disk drive Software MS DOS 5 0 or later ASPI drivers for the host adapter if the DAC960 Series controller is connected to the computer via a SCSI HBA SLPCF drivers for the terminal emulation program if the DAC960 Series controller is connected to the computer via a serial communica tions port DACCF Utilities Introduction to DACCF Installing DACCF Procedure DACCF should be run from a floppy diskette We recommend you make a backup copy of the DACCF Configuration amp Utilities diskette on a bootable diskette
31. write back policy 6 Once the appropriate option is selected the configuration is saved and a summary screen Figure 3 18 is displayed This summary screen dis plays the operating parameters for the configuration MYLEX Disk Array Controller Configuration Utility Version nem nn dd uy n Channel nn Target DACI66XX tn Firmware version n m Automatic Configuration 1 5 Enabled Number of System drives Raid Level Write Cache Number of Physical drives Available Capacity 658 MB Automatic configuration successfully done Make sure to INITIALIZE System drive 6 before exiting this utility t Figure 3 18 Automatic Configuration Summary Screen 7 Press any key to return to the Main menu and proceed directly to Initialize the System Drives on page 3 34 Manual No 771953 3 19 Preparing the Array New Configuration Select this option to manually configure the disk array for the first time or to reconfigure the array This option will create a new configuration overwrit ing any existing array configuration To change the write policy of an exist ing configuration or to add additional drive packs use the View Update Configuration item on the Main menu WARNING Overwriting an existing configuration will result in the complete and irreversible loss of any data stored on disk drives in the array Use this option with caution Define Drive Groups To define drive groups follow the procedu
32. 7 Hardware Parameters 4 29 Battery Backup rot ciet ER cede sale A RC dc ct 4 30 Automatic Rebuild Management 4 31 Operational Fault Management 4 31 Physical Parameters 4 31 Default Rebuild Rate 4 32 Controller Read Ahead 4 32 Super Read Ahead DAC960S Only 4 33 Segment SIZe 25 8 veri rene a E ae 4 33 Vii Stripe SIZe hi tai a 4 34 Logical Sector Size DAC960S Only 4 34 Physical Sector Size DAC9608 Only 4 34 SCSI Transfer Parameters 4 34 Data Transfer Rate MHZ 4 36 Command Tagging 4 37 SCSI Data Bus Width 4 37 Startup Parameters 4 37 Spin UP OPON 5i ur ex ie ia 4 38 Number of Devices Per Spin 4 39 D la ax bin bee SE UELLE GR Dx 4 39 Device Management 4 40 Ko P MC MEL 4 40 Bad Block Table Bad Data Table 4 41 Error Counts fora Device 4 42 Appendix A DACCF File List Host Based DAC960 Products
33. BY 5 SBY 0 1 SBY 0 A amp B 5 0 SBY A amp B 0 1 0 SBY B 5 SBY B 0 1 SBY A 5 B 5 A amp B 5 0 A 0 1 B 0 1 A amp B 0 1 0 0 0 5 SBY 0 1 SBY 5 SBY 0 1 SBY 0 0 gt gt gt lwuw gt gt l gt gt gt l gt gt gt W gt 0U0U gt S gt 0U0 gt Effective Capacity ZA sr A dl ld nm m 3 5 rj qe 2 5 2 qu m 45 3 A amp B 4 A amp B 3 pes 1 5 A 3 B 3 A amp B 6 A 2 DPPpUUPP 2rr 2P r rommoouem 00 D pUUPP IUPPU a oORANN AA 2 23 Configuration Strategies 2 24 DACCF Utilities Chapter 3 Preparing the Array Overview The following is an overview of the steps necessary to prepare an array Each step is described in greater detail later in this chapter 1 Start DACCF Invoke DACCF from the MS DOS prompt Optimize the controller parameters for your application Although the DAC960 ships from the factory optimized to work in a variety of environments certain changes can be made to the controller s settings This is the best time to make these optional changes Low level format the array s SCSI drives It s a good idea to low level format the SCSI drives with the DAC960 controller so that any media defects can be discovered and catalogued Define and configure one or more physical drive groups or packs Either use the automatic configuration option or define your own drive groups also known as
34. Configuration Uieu lpdate Configuration Rebuild Initialize System Drive Consistency Check Tools Select DACI64 fiduanced Functions Diagnostics Choose this option to perform special operations like lou level format of physical drive s backup restore print and clear the existing configuration Figure 3 6 Tools Option The Tools menu will appear after a short interval Figure 3 7 DACCF Utilities Preparing the Array A representation of the physical devices in the array will be displayed on the left side of the screen and the Tools menu appears on the right side of the screen MYLEX Disk Array Controller Configuration Utility Version n nmn nn dd uy n Channel nn Target DACIGBXX tn Firmware version n m Tgt Channel Number ID A 1 Tools aL pr 1 Bad Block Tahle 2 pet SECUS ES E ione Con gara Lion 4 EA Ll 8 Print Configuration Press FZ to View full Display Figure 3 7 Tools menu 2 Select Format Drive from the Tools menu The highlight bar will be positioned on the first device on the first channel of the array Figure 3 8 MYLEX Disk Array Controller Configuration Utility Version nem nn dd uy n Channel nn Target DACI6HXX tn Firmware version n m Tgt Channel Number ID A 1 Tools aL pr 1 Bad Block Table A pet 5 Mill Drive L3 p E ione Con gue Lion 4 EA Ll 8 Print Configurat
35. Disk Array Controller Configuration Utility Version n m nn dd uy n Channel nn Target DACIGBXX iin Firmware version n m Tgt Channel Number ID 4 1 Tools NL 6 C Crad 1 Bad Block Table NL 2 Error Counts 1 CA ES 17 3 Format Drive BY NL 4 Make Online 20 5 1 5 Kill Drive NL 6 Backup Restore conf 3 mee Y Clear Configuration NE Ll 8 Print Configuration 4 NL 5 BANI ET Enter File Name NL ela CA gt MIDA Figure 4 24 Specify the Filename Containing the Configuration 2 A confirmation box Figure 4 25 will appear MYLEX Disk Array Controller Configuration Utility Version n nn nn dd uy n Channel nn Target DACIGBXX iin Firmware version n m Tgt Channel Number ID A 1 Tools NL 6 C Crad 1 Bad Block Table NL 2 Error Counts 1 CA ES 17 3 Format Drive BY NL 4 Make Online 20 5 1 5 Kill Drive NL 6 Backup Restore conf 3 me Y Clear Configuration LI Ll 8 Print Configuration 4 NL 5 males C Do you really want to e Ll Restore Configuration 7 6 1 E NENNEN YES Figure 4 25 Restore Confirmation Box 4 22 DACCF Utilities Administering the Array Select YES to restore the configuration The configuration will be copied from the diskette to the array s non volatile memory WARNING Restoration of an array configuration will c
36. EAD drive 4 DACCF will ask you if you want to low level format the drive Figure 4 9 MYLEX Disk Array Controller Configuration Utility Version n nn mmddyy n Channel nn Target DACIGBXX iin Firmware version n m REBUILD Tgt Channel Number 1 Ca E ea A A A E a MEE ET C Do you want to Format EN co before rebuilding 7 Figure 4 9 Format Before Rebuilding Manual No 771953 4 9 Administering the Array Select YES if this is a new drive that has not been used in this array before allow the drive to be low level formatted before the rebuild takes place Any defined system drives will then be rebuilt on the new drive in sequential order Select NO to skip the low level format and proceed directly to the rebuild of data on the new drive 5 Press the Enter key to initiate the rebuild 6 The rebuild status screen Figure 4 10 will appear showing the progress of data reconstruction on all of the system drives that are dependent on the selected physical drive System drives are rebuilt sequentially beginning with the system drive with the lowest numerical value MYLEX Disk Array Controller Configuration Utility Version n nn nn dd uy n Channel nn Target DACIGBXX iin Firmware version n m REBUILD Tgt Channel Number ID 8 1 A H System Drive B 31x Lie Figure 4 10 Rebuild Drive Status
37. EX Disk Array Controller Configuration Utility Version n nmn nn dd uy n Channel nn Target DACIGBXX tn Firmware version n m Tgt Channel Number Pack Definition ID 6 1 RDY 1 Create Pack 6 C C Z Cancel Pack RD Y 3 Arrange Pack 123 C 4 Device Information NL RDY 20 C Cc 5 7 Device Information 3 JL ES Vendor CONNER ONL Model No CFPi1B6BE LK SE C Revision 2835 NL E CA Size 1813 MB a o m Channel Target rS Figure 3 26 Getting Device Information 3 26 DACCF Utilities Preparing the Array The device information window displays the device manufacturer model number firmware revision and size as reported by the SCSI inquiry and read capacity commands The channel to which the device is attached as well as the SCSI ID of the device are also displayed 3 4 To select another device press any key to return to the drive matrix box and repeat step 2 to select and display the properties of a different device To return to the pack definition menu press the ESC key Defining and Creating a System Drive After drive groups have been arranged they are used to create system drives System drives have the following properties Each system drive has a defined capacity which is less than or equal to the total capacity of the drive group on which it resides Maximum size of a system drive is 32GB when using DAC960 Firmware versi
38. LINE Notice that the same term online is used for both physical and logical drives Online A Logical Drive is in an online state if All of its participating SCSI drives are online Critical A Logical Drive is in a critical state if It has been configured at RAID level 1 5 or 0 1 and One and only one of its SCSI drives is not online A logical drive is considered critical because any failure of another of its SCSI drives may result in a loss of data Note I O operation can only be performed with system drives that are online or critical Offline A Logical Drive is in an offline state if No data can be read from it or written to it Manual No 771953 G 3 Glossary System commands issued to offline logical drives are returned with an error status no operations can be performed on offline logical drives A logical drive can be offline under one of two situations described below e Itis configured with a redundant RAID level 1 5 or 0 1 and two or more of its SCSI drives are not online or e Itis configured at RAID level 0 JBOD or in a spanned set and one or more of its SCSI drives are not online Logical Drives See System Drives Mirroring Refers to the 100 duplication of data on one disk drive to another disk drive Each disk will be the mirror image of the other Pack See Drive Groups or Drive Packs Parity See Rotated XOR Redundancy
39. MWLEX DACCF Utilities Installation Guide and User Manual Part Number 771953 D02 O Copyright 1996 Mylex Corporation All Rights Reserved All contents of this manual are copyrighted by Mylex Corporation The information contained herein is the exclusive property of Mylex Corporation and shall not be copied transferred photocopied translated on paper film electronic media or computer readable form or otherwise reproduced in any way without the express written permission of Mylex Corporation Notice This Manual describes the Mylex Disk Array Configuration Utilities DACCE software Although reasonable efforts have been made to assure the accuracy of the information contained herein this publication could include technical inaccuracies or typographical errors Mylex Corporation expressly disclaims liability for any error in this information and for damages whether direct indirect special exemplary consequential or otherwise that may result from such error including but not limited to loss of profits resulting from the use or misuse of the manual or information contained therein even if Mylex Corporation has been advised of the possibility of such damages Any questions or comments regarding this document or its contents should be addressed to Mylex Corporation at the address shown on the cover The following paragraph does not apply to the United Kingdom or any country where such provisions are inconsistent with local l
40. Note The initialization rate for a given system drive is dependent upon the size of the drive and the RAID level specified for the drive Therefore some system drives will initialize more quickly than others WARNING Do not interrupt the initialization process 7 At the conclusion of the initialization a message Figure 3 41 is displayed Press any key to return to the Main menu 3 38 DACCF Utilities Preparing the Array MYLEX Disk Array Controller Configuration Utility Version nem nn dd uy Firmuare version n m n Channel nn Target DACIGBXX tn Initialize System Drive ass sal 1844 Initialized Sus Dru 4 Iz 144 Initialized Sys Drv 1 Figure 3 41 After Initialization Has Finished Preparation of the array is complete at this point You can exit DACCE at this time and proceed to load the operating system onto the array Exiting DACCF To exit DACCE follow these steps 1 Get to the Main menu 2 Press the ESC key The Exit confirmation box will appear Select YES to exit DACCF and return to the MS DOS command prompt Select NO to remain in DACCF Manual No 771953 3 39 Preparing the Array 3 40 DACCF Utilities Chapter 4 Administering the Array Overview During the operational life of the array you may have a need to make addi tions or changes to certain properties of the configuration while retaining the existing configuration For example you may want to increase
41. Parameters larduare Parameters Physical Paraneters SCSI Xfr Paraneters Startup Paraneters Choose this option to view or edit the controller s changeable Hardware features like battery backup Figure 4 31 Hardware Parameters Option Manual No 771953 4 29 Administering the Array The Hardware Parameters menu appears Figure 4 32 MYLEX Disk Array Controller Configuration Utility Version n nn nn dd uy n Channel nn Target DACIGBXX tn Firmware version n m Harduare Parameters Battery Backup Disab led Array Encl Mgmt I F CAEMI Disabled StorageWorks Fault Mgmt IM Enabled Figure 4 32 Hardware Parameters Menu To change a hardware parameter do the following 1 Highlight the desired parameter using the cursor keys 2 Press the Enter key to change the value 3 When the correct value is displayed either Repeat steps 1 amp 2 above but for a different parameter or Press the ESC key to return to the Edit View Parameters menu The change will be retained Battery Backup Enable the battery backup option if you have installed a Mylex DBBU960 type battery backup module on your DAC960 Series controller When installed and enabled the battery backup unit will provide the required power should a power loss occur protecting data on your arrays See the DBBU960 Battery Backup Module User s Manual Manual No 771931 for further details on
42. QOP oooooo 000000 00000 0000 00 w jo gt gt 000 00 UJ A 000 B ooo Manual No 771953 Possible RAID Levels A 5 A 5 SBY A 5 A 5 SBY A 0 1 SBY B 0 B 1 A 5 B 5 A amp B 5 0 A 0 1 B 0 1 A amp B 0 140 Effective Capacity Ad mn ld k 5 3 qe 2 5 4 o 2 1 p 1 5 2 1 2 B 2 A amp B 4 A 1 5 B 1 5 A amp B 3 D UUPPUUPPPIPP nmoos 2 21 Configuration Strategies Table 2 7 Array Configuration Strategies Continued Drives Y Possible Effective Drive Groups RAID Levels Capacity A 0 A JBOD A 1 B o B JBOD B 1 C 0 C JBOD C 1 D 0 D JBOD D 1 E o E JBOD E 1 F o F JBOD F 1 G o G JBOD G 1 A 0000000 A 5 A 6 A 0 1 A 3 5 A 000000 A 5 SBY A 5 A 0000 A 5 SBY A 3 B 00 A 0 1 SBY A 2 o B 0 B 2 B 1 B 1 A 000 A 5 SBY A 2 B ooo B 5 SBY B 2 o A amp B 5 0 SBY A amp B 4 A 0 1 SBY B 0 1 SBY A 1 5 A amp B 0 1 0 SBY B 1 5 A amp B 3 2 22 DACCF Utilities Configuration Strategies Table 2 7 Array Configuration Strategies Continued Possible RAID Levels Drives amp Drive Groups Eight drives o ooooooo A B C D E F G H lo A 00000000 gt 0000000 A 00000 B 00 A 000 B 000 00 A 0000 B 0000 A 0000 B 000 Manual No 771953 5 SBY 0 1 SBY 0 5 SBY 0 1 SBY 0 1 S
43. Refers to a SCSI drive s current operational status At any given time a SCSI drive can be in one of five states READY ONLINE STANDBY DEAD or REBUILD The controller stores the state of the attached SCSI drives in its non volatile memory This information is retained even after power off Hence if a SCSI disk is labeled DEAD in one session it will stay in the DEAD state until a change is made either by using a system level utility or after a rebuild Each of the states is described below Ready A SCSI disk drive is in a ready state if it Is powered on and Is available to be configured during the current session but remains uncon figured Online A SCSI disk drive is in an online state if it Is powered on and Has been defined as a member of a drive group and Is operating properly Standby A SCSI disk drive is in a standby state if it Is powered on and Is able to operate properly and Was NOT defined as part of any drive group Dead A SCSI disk drive is in a dead state if it Is not present or If it is present but not powered on or If it failed to operate properly and was killed by the controller G 6 DACCF Utilities Glossary When the controller detects a failure on a disk it kills that disk by chang ing its state to dead A SCSI drive in a dead state does not participate in any I O activity No commands are issued to dead drives Rebuild A SCSI disk drive is i
44. Toggle Write Policy To change write policy described earlier and also in the Glossary of any system drive use the following procedure 1 Select Toggle Write Policy from the System Drive Definition menu Figure 3 32 The cursor will move to the System Drive Table MYLEX Disk Array Controller Configuration Utility Version n nn nn dd uy n Channel nn Target DACI66XX tn Firmware version n m Pak4 Drvus Size MB System Drive Definition AY 3 3439 1 Create Systen Drive z Toggle Write Policy Sus Dru Size MB RAID Write Mode 5 Figure 3 32 Selecting the Write Policy for a System Drive 2 Use the cursor keys to highlight the desired system drive 3 Press the Enter key to toggle or change the write policy for that system drive The allowed policies are WRITE THRU and WRITE BACK 4 Repeat steps 2 and 3 above to select and change write policies for other system drives if any 5 When the write policies are set correctly on all desired system drives press the ESC key to return to the System Drive Definition menu 3 32 DACCF Utilities Preparing the Array Saving the New Configuration Once all of the system drives are defined the configuration should be saved to the DAC960 controller s memory To save the configuration 1 From the System Drive Definition menu press the ESC key twice 2 A confirmation dialog box will be
45. a different access profile that means the type and frequency of read and write activity that is performed against the array over the course of time Identifying the data access profile will help you determine a strategy favoring capacity availability or performance Manual No 771953 2 1 Configuration Strategies For example so called video servers typically write data i e the video clip infrequently but play back the data very often The ratio of reading to writing in this type of an array is far different from a general purpose file server that s doing small read and write operations all day long In addition the characteristics of the files themselves are very different video and image files are typically very large when compared to letters memos and spreadsheet files Video server applications or in general all imaging applications need to read very large segments of data compared to the rela tively small data segments found with spreadsheet or text documents RAID Essentials for DAC960 Series Controllers You ll get a better idea of how to configure your disk array if you under stand how DAC960 Series controllers implement RAID technology and organize the disk drives Correct installation of the disk array and the con troller requires a proper understanding of RAID technology and the concepts described in this chapter RAID is an acronym for Redundant Array of Independent Disks DAC960 Series controllers i
46. a loss could result from this action Select NO to cancel the restoration of consistency between the data and parity information contained on this system drive If you are unsure that you have a backup copy of the data on this system drive select the NO option make a backup of the information on the system drive and then perform the consistency check 7 Press the Enter key to start the process Manual No 771953 4 15 Administering the Array 8 The consistency check status screen Figure 4 17 will appear showing the status of the operation MYLEX Disk Array Controller Configuration Utility Version n nn nndd yy n Channel nn Target DACI66XX tn Firmware version n m Consistency Check res 234 Checked D Sus Dru A Figure 4 17 Consistency Check Status Screen 9 Atthe conclusion of the check a message indicating success will be displayed Figure 4 18 Press any key to return to the Main menu MYLEX Disk Array Controller Configuration Utility Version n nmn nndd yy n Channel nn Target DACIGBXX tn Firmware version n m Consistency Check Lo all 18H Checked Sys Drv 8 ooo ES Figure 4 18 Consistency Check Complete 4 16 DACCF Utilities Administering the Array Configuration Management The configuration of your array disks drive groups RAID levels as well as other parameters is stored in two memory locations on the DAC960 control ler However Myle
47. able segment size settings to use for each stripe size The default segment size for Mylex DAC960 Series controllers is 8K Table 3 1 Segment Sizes for Each Stripe Size Stripe Size Select Segment Size 8k 8K 16K 16K 32K 32K 64K 1K 2K 8k 64K a Default Firmware version below 2 6 b Default Firmware version at or above 2 6 A large segment size 64K is useful when accompanying a 64K stripe size for applications requiring large sequential reads or writes such as video playback from disk However it can actually hinder system performance if files are smaller or if data access is more random than sequential Small seg ment sizes especially 8K are best for most data processing situations Manual No 771953 3 9 Preparing the Array Low Level Format the Drives Before starting the configuration for the first time Mylex recommends that you low level format the drives used in the array Low level formatting will completely erase any existing data on the drives and perform a media surface check This procedure is described below WARNING Low level formatting will destroy any data on the disk drive Procedure 1 Select Tools from the Main menu Figure 3 6 MYLEX Disk Array Controller Configuration Utility Version n nn nndd yy n Channel nn Target DACI6BXX iin Firmware version n m Hain Menu Bi a2 63 Ba B3 B6 B BB aa 1B Automatic Conf iguration Meu
48. ached to the same controller e All of the system drives that are dependent on the failed disk are redun dant system drives e g RAID 1 RAID 5 RAID 0 1 Manual No 771953 G 7 Glossary Note The standby rebuild will only happen on the SAME DAC960 controller never across DAC960 controllers A Standby disk can be created in one of two ways 6 When a user runs DACCF utility all disks attached to the controller that are NOT configured into any drive group will be automatically labeled as standby drives 7 A disk may also be added attached at a later time to a running system and labeled as standby by using the DAC960 Software Kit see appro priate chapters for DAC960 utilities for a particular operating system During the automatic rebuild process system activity continues as normal System performance may degrade slightly during the rebuild process To use the standby rebuild feature you should always maintain a standby SCSI disk in your system When a disk fails the standby disk will automati cally replace the failed drive and the data will be rebuilt The system admin istrator can disconnect and remove the bad disk and replace it with a new disk The administrator can then make this new disk a standby The standby replacement table has a limit of 8 automatic replacements in any session from power on reset to the next power off reset When the limit of 8 is reached and a disk failure occurs the stand
49. ance cache Sometimes referred to as Mylex RAID 7 Benefits Cache reduces the amount of time the computer has to wait for a disk to get to the right place to read or write data Drawbacks Does not provide data redundancy and does not use striping for performance enhancements Drives Minimum 1 Maximum 1 Manual No 771953 2 5 Configuration Strategies Managing Physical Drives and SCSI Devices You must organize physical disks into drive groups and logical drives that can support the various RAID levels Physical disk drives are connected to one or several of the DAC960 SCSI channels as shown below When using a DAC960 Series controller with two or more channels it is recommended that disk drives be evenly distributed among the available SCSI channels for optimal performance This will mini mize the effect of any overhead relative to the SCSI bus arbitration scheme DAC960 Series controllers can also be used to control non disk SCSI devices To maximize disk drive performance however tape CD ROM and other non disk SCSI devices should be connected together on a separate channel The example below shows a three channel DAC960 DAC960 Drive Groups Organize the disk drives into drive groups or packs after they are con nected to the controller formatted and initialized these procedures are described in Chapter 3 Preparing the Array Up to eight drive groups are supported per controller Dr
50. and run the program from this diskette 1 Create a bootable floppy disk using the MS DOS Format utility with the S parameter For example if your floppy disk drive is designated as A enter the following command at a DOS command prompt FORMAT A S 2 Copy the programs DACCF EXE and DACD EXE from the DAC960 Configuration amp Utilities diskette to the bootable floppy disk The pro grams are located in the DACCF directory of the utility disk Alternatively MS DOS Diskcopy can be used to create a backup copy of the utility disk For more information on using this utility consult the MS DOS reference materials that accompanied your system Adding SCSI to SCSI Drivers When the system uses a DAC960 Series SCSI to SCSI controller additional files are needed on the bootable floppy For controllers that are connected to the host system through a SCSI host bus adapter HBA you should also copy the HBA s ASPIxxxx SYS device driver onto the bootable floppy where xxxx represents the manufacturer s specific device driver name For systems that are communicating with a DAC960S Series SCSI to SCSI controller through a serial port a null modem cable connected between COMI on the host and the serial port on the controller you should copy either the SLPITK EXE or TERM7 EXE utility onto the bootable floppy depending on the requirements for your terminal or terminal emulation software Make sure that the appropriate driver will load
51. annot be accessed otherwise Are there command line switches or arguments for DACCF See Appendix C B 4 DACCF Utilities Appendix C Command Line Arguments DACCF can be started with additional command line arguments or parame ters These parameters and their functions are presented below Multiple arguments can be supplied if separated by a space The syntax for supplying the arguments is as follows DACCF argumentl argument2 argument3 WARNING Some command line arguments can potentially cause data loss if used improperly Use caution when running the DACCF program with one or more arguments Parameter Function S This is used to configure the DAC960S when you are using serial port COM to configure the array A null modem cable must connect the COM port of the computer to the serial interface on the DAC960S All communication with the controller is then accomplished via the serial link ddfc This sets a bit to disable a disconnect on first command by any device on the SCSI bus This switch is available to fix a problem seen in some devices that try to negotiate on a reconnect a function which is not supported by the DAC960 Seagate Hawk drives with some firmware levels some Seagate Barracuda drives and some older IBM drives are known to attempt to do this If a drive is not seen on power up but can be accessed after a warm boot this could be the problem If you see a drive go off line for no apparent reason
52. arrays Always back up all of the drives before making a stripe size change and always reconfigure and initialize the logical array after a new stripe size is saved Logical Sector Size DAC960S Only The logical sector size shown only for DAC960S controllers is fixed at 512 bytes and cannot be altered The menu option only allows you to view the parameter Physical Sector Size DAC960S Only The physical sector size of a disk drive shown only for DAC960S control lers is dependent upon the disk drive and also cannot be altered The menu option only allows you to view the parameter SCSI Transfer Parameters SCSI transfer parameters control the interaction between SCSI devices and the host adapter To change any SCSI transfer parameter below select SCSI Xfr Parameters from the Edit View Parameters menu Figure 4 35 4 34 DACCF Utilities Administering the Array MYLEX Disk Array Controller Configuration Utility Version nem nn dd uy n Channel nn Target DACIGBXX tn Firmware version n m Edit Vieu Parameters Hardware Paraneters Physical Parameters SCSI Xfr Parameters Startup Paraneters Choose this option to view or edit the controller s changeable SCSI transfer parameters like wide SCSI etc Figure 4 35 SCSI Transfer Parameters Option A dialog box appears requesting that you select the channel whose SCSI transfer parameters you would like to change Figu
53. artup Parameters Choose this option to view or edit the controller s changeable physical parameters like sector size stripe size etc Figure 4 33 Physical Parameters Option Manual No 771953 4 31 Administering the Array The Physical Parameters menu appears Figure 4 34 MYLEX Disk Array Controller Configuration Utility Version n m nn dd uy n Channel nn Target DACIGBXX tn Firmware version n m Physical Parameters Default rebuild rate Eli Controller read ahead Enabled Segment Size K bytes Stripe size K bytes 64 Figure 4 34 Physical Parameters Menu To change a physical parameter do the following 1 Highlight the desired parameter using the cursor keys 2 Press the Enter key to change the value 3 When the correct value is displayed either Repeat steps 1 amp 2 above but for a different parameter or Press the Esc key to return to the Edit View Parameters menu The change will be retained Default Rebuild Rate The rebuild rate is a relative indication of how much time the controller devotes to a rebuild operation Integer values from 0 50 can be defined For low rebuild priority and high array performance specify a value of 0 For high rebuild performance and reduced array performance during rebuild select 50 Controller Read Ahead The Controller Read Ahead function improves data retrieval performance by allowing the con
54. aw MYLEX CORPORATION PROVIDES THIS PUBLICATION AS IS WITHOUT WARRANTY OF ANY KIND EITHER EXPRESS OR IMPLIED INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE Some states do not allow disclaimer of express or implied warranties or the limitation or exclusion of liability for indirect special exemplary incidental or consequential damages in certain transactions therefore this statement may not apply to you Also you may have other rights which vary from jurisdiction to jurisdiction Information in this publication is subject to change without notice and does not represent a commitment on the part of Mylex Corporation Changes may be made periodically to the information herein these changes will be incorporated in new editions of the publication Mylex Corporation reserves the right to make improvements and or changes at any time in the product s and or program s described in this publication It is possible that this publication may contain reference to or information about Mylex Corporation products machines and programs programming or services that are not announced in your country Such references or information must not be construed to mean that Mylex Corporation intends to announce provide or make available such Mylex products programming or services in your jurisdiction Requests for technical information about Mylex Corporation products should be made to your
55. bad blocks encountered during a rebuild or consistency check process The Write Back Bad Block Table stores information on all irrecoverable write back errors that occur DACCF provides commands that allow you to see either of these two tables Cache Controller memory used to speed up data transfer to and from a disk Cache Flush Refers to an operation where all unwritten blocks in a Write Back Cache are written to the target disk This operation is necessary before powering down the system Cache Line Size See Segment Size Channel Refers to one SCSI bus on a DAC960 Series controller Each DAC960 provides at least one channel and additional channels with optional upgrades Consistency Check Refers to a process where the integrity of redundant data is verified For example a consistency check of a mirrored drive will make sure that the data on both drives of the mirrored pair is exactly the same For RAID Level 5 redundancy a consistency connect is a function that allows a target SCSI device typically a disk drive that received a request to perform a rela tively long I O operation to release the SCSI bus so that the controller can send commands to other devices When the operation is complete and the SCSI bus is needed by the disconnected target again it is reconnected Manual No 771953 G 1 Glossary Disk Failure Detection The controller automatically detects SCSI disk failures A monitoring pro cess run
56. by replacement will occur but will not be recorded in the replacement table To clear the standby replacement table reboot the system from a DOS bootable floppy run the configuration utility and select the option view update configuration from the main menu A red box labeled Drive Remap List will be displayed Selecting the box will allow you to continue You should save the configuration without making any changes and exit the con figuration utility This will clear the replacement table You may now pro ceed to boot your system and continue normal operations In normal use the replacement table limit of 8 should not cause any prob lems Assuming that a disk fails about once a year drives we support gener ally come with a 5 year warranty the system would run continuously for a minimum of 8 years before the table would need to be cleared G 8 DACCF Utilities Glossary Stripe Order The order in which SCSI disk drives appear within a drive group This order must be maintained and is critical to the controller s ability to Rebuild failed drives Stripe Size The stripe size is defined as the size in kilobytes 1024 bytes of a single I O operation A stripe of data data residing in actual physical disk sectors which are logically ordered first to last is divided over all disks in the drive group Stripe Width The number of striped SCSI drives within a drive group Striping Refers to the storing
57. check Any data placed on uninitialized system drives is at risk Initialization Procedure To initialize one several or all recommended system drives follow the steps below 1 Select Initialize System Drive from the Main Menu Figure 3 34 MYLEX Disk Array Controller Configuration Utility Version n nn nn dd uy n Channel nn Target DACI6BXX tn Firmware version n m Main Menu H1 Automatic Configuration BZ Heu Configuration H3 View Update Configuration B4 Rebuild 46 Consistency Check 47 Tools BB Select DACI64 49 Advanced Functions 18 Diagnostics Choose this option to initialize one or more System drives simultaneously Figure 3 34 Initialize System Drive Option 2 Choose Select System Drive from the Initialize System Drive menu Figure 3 35 3 34 DACCF Utilities Preparing the Array MYLEX Disk Array Controller Configuration Utility Version nem nn dd uy n Channel nn Target DACI66XX tn Firmware version n m Initialize System Drive 1 Select Systen Drive 2 Start Initialize Choose this option to select System drives for initialization Figure 3 35 Initialize System Drive Menu The Initialize System Drive screen will appear Figure 3 36 MYLEX Disk rray Controller mfiguration Utility Version n m n Channel nn Target DACI6BXX iin Firmuare version
58. d press the Enter key Command Line Parameters DACCF can be started with additional parameters Appendix C contains an explanation of the most useful command line arguments which can be supplied Opening Screens Normally DACCF will locate the DAC960 Series controller and scan the SCSI device chains attached to it During this process a screen similar to Figure 3 3 will be displayed Inquiring the devices connected to the adapter Channel B Target ID 5 Initializina tables please wait Figure 3 3 SCSI Device Scan This screen will be followed by the DACCF Main menu as shown in Figure 3 4 Manual No 771953 3 5 Preparing the Array MYLEX Disk Array Controller Configuration Utility Version nem nn dd uy n Channel nn Target DACI66XX tn Firmware version n m Main Menu BZ New Configuration B3 View Update Configuration B4 Rebuild H5 Initialize System Drive 46 Consistency Check B7 Tools BB Select DACI64 49 Advanced Functions 18 Diagnostics If 3 or more Physical drives are present choose this option to create one RAID 5 System drive automatically Figure 3 4 DACCF Main Menu Problems If you do not see these two screens in succession a problem may exist Refer to Appendix D for more information on problems and how to resolve them 3 6 DACCF Utilities Preparing the Array Select DAC960 DACCF operates upon a single DAC960 Serie
59. drive group is six drives but the effective capacity will be less after normal RAID capacity utilization is taken into account DAC960 SBY A B System Logical Drives After all the physical drive groups are defined and arranged one or more system drives must be created System drives are the logical drives that are presented to the operating system A system drive s capacity can encompass any portion of a drive group up to the total capacity of that drive group or the capacity of more than one drive group up to four drive groups Up to eight system drives can be created with DAC960 firmware versions below 2 6 With firmware versions at or above 2 6 up to 32 system drives can be created per controller The follow ing illustration shows a RAID 0 1 configuration with three mirrored system drives created in a drive group containing three disk drives DRIVE GROUP A 3 Drives ry ae on Gar eae Mirrored System Drives AO A2 2 8 DACCF Utilities Configuration Strategies Assigning RAID Levels to System Drives Each system drive has a defined RAID level 0 1 5 0 1 JBOD based on the number of drives in the drive group upon which it is created If a drive group has enough drives to support several different RAID levels the sys tem drive can be assigned any of the available levels However a system drive may have only one RAID level DRIVE GROUP B 3 Drives 3 RAID 5 7 RAID 0 1 d PT
60. e 3 28 Toggle Write Policy 3 32 Saving the New Configuration 3 33 Initialize the System Drives 3 34 Initialization Procedure 3 34 Exiting DAGGE cui tite aa eres 2 aa die Med Moe Ru Cas 3 39 Chapter 4 Administering the Array OVOIVIOW inrit ria rens a ai DE Rab M e Bub ii 4 1 Viewing Updating the Configuration 4 1 Changing the Existing Write Policy 4 3 Create New Standby Drives 4 5 Create New Drive Groups and System Drives 4 6 View the Existing Configuration 4 6 Saving the Updated Configuration to Memory 4 7 Rebuild Drives ss e pe oce m eae ees 4 8 Consistency Check 4 12 Configuration Management 4 17 Backup Restore Configuration 4 18 Backup Configuration 4 20 Restore Configuration 4 22 Clear Configuration 4 23 Print Configuration 4 25 Advanced Functions se ee Re ce Re 4 2
61. e 2 Start Initialize 1 Select System Drive Choose this option to initialize selected System drives Figure 3 38 Return to the Initialize System Drive Menu 3 36 DACCF Utilities Preparing the Array 5 Select Start Initialize from the Initialize System Drive menu A confirmation box Figure 3 39 will appear MYLEX Disk Array Controller Configuration Utility Version nem nn dd uy n Channel nn Target DACI6BXX iin Firmware version n m Initialize System Drive Esad Sus Dru Iis Sys Dru 1 y Do you want to proceed with Initialization 7 YES Figure 3 39 System Drive Initialization Confirmation Note Once the system drive initialization is started it cannot be aborted Select YES to start the initialization of the selected system drives Select NO to abort the process and return to the Initialize System Drive screen Manual No 771953 3 37 Preparing the Array 6 The initialization status screen Figure 3 40 will be displayed with the initialization progress of each drive included in the operation MYLEX Disk Array Controller Configuration Utility Version n m nn dd uy n Channel nn Target DACI6BXX tn Firmware version n m Initialize System Drive El 154 Initialized Sus Dro 8 _ Esc 42x Initialized gt Sys Dre 1 Figure 3 40 System Drive Initialization Status
62. e your array for the greatest possible capacity To see the relationship between the different RAID levels and effective capaci ties offered for the quantity X drives of N capacity refer to Table 2 3 As an example computed capacities for five drives of size 2GB each are provided Table 2 3 RAID Levels and Effective Capacity RAID Effective Example Level Capacity in GB ENE On 22 5 As you can see the greatest capacities are provided by RAID 0 and JBOD Mylex RAID 7 with the entire capacity of all disks being used Unfortu nately with these two solutions there is no fault tolerance RAID 5 gives the next best capacity followed by RAID 1 or RAID 0 1 Manual No 771953 2 11 Configuration Strategies Configuring for Maximum Availability When considering optimizing for availability it s important to understand some of the terminology concerning the condition of array operation These definitions are presented in Table 2 4 Table 2 4 Array Operational Conditions Array Condition Meaning Normal The array is operating in a fault tolerant mode and can sustain a drive failure without potential data loss Critical The array is functioning and all data is available but the array cannot sustain a drive failure without potential data loss Degraded The array is functioning and all data is available but the array cannot sustain a drive failure without potential data loss Additionally a reconstruction or rebuild opera
63. ect a RAID level for each drive group that will best meet the capacity availability and performance needs for your particular application Manual No 771953 2 17 Configuration Strategies Key Points About the Tables Here are some key points to consider when using the tables 2 18 To determine the approximate capacity of a particular configuration assume that each physical disk has a unit capacity of one The value in the Effective Capacity column will indicate the effective available capacity for a drive group with a given RAID level A configuration is fault tolerant or has enhanced availability if there is an asterisk after the value in the Effective Capacity column The number of asterisks is proportional to the level of fault tolerance or availability that a configuration will exhibit The more asterisks the better the fault tolerance To determine the performance of a given configuration correlate the configuration s RAID level with the application as presented in Table 2 6 on page 2 15 Drives that are not affiliated with a drive group are assumed to be hot spare or standby drives and provide an additional measure of fault tol erance The use of standby drives with redundant RAID levels is indi cated in the Possible RAID Levels column as SBY In most of the configurations multiple RAID levels can exist for a given drive group These multiple RAID levels can be implemented in the same drive group on different system
64. ed and the drive s that are not part of a drive group will remain in the RDY state Manual No 771953 4 5 Administering the Array Create New Drive Groups and System Drives To create new drive groups and system drives do the following 1 Select Define Pack from the View Update Configuration menu 2 Follow the instructions presented in New Configuration in the previ ous chapter This includes creating and arranging drive groups defining system drives and setting RAID levels and write policy View the Existing Configuration If no devices have been added to the array and no changes in write policy are planned then navigation through either option of the View Update Configu ration menu is equivalent to viewing the configuration 4 6 DACCF Utilities Administering the Array Saving the Updated Configuration to Memory After making changes to write policy on existing system drives or creating new system drives the configuration should be saved to the DAC960 controller s memory To save the configuration 1 From the System Drive Definition menu press the Esc key twice 2 Aconfirmation dialog box will be displayed Figure 4 6 MYLEX Disk Array Controller Configuration Utility Version n nn nndd yy n Channel nn Target DACIGBXX tn Firmware version n m Pak Drus Size MB SAVE configuration 7 Ar 3 987 B 2 2826 YES O ero
65. elow What is the procedure to set up a RAID 0 1 5 6 7 system See the Overview in Chapter 3 Preparing the Array for a quick summary of the steps A RAID system will require several disks for redundancy How many drives are needed to setup a RAID 0 1 5 6 7 system Minimum Number of Drives RAID Levels Available 1 Mylex RAID 7 also known as JBOD 2 0 1 3 or more 0 5 0 1 also known as Mylex RAID 6 I get a message adapter not responding to command What does this mean and what should I do This error indicates a time out condition with a SCSI device either the con troller or one of the devices on the SCSI chain To determine the location of the problem remove all cabling from the controller and try to run DACCF again If the error persists the controller needs servicing If the error does not reappear then check your devices and cabling Manual No 771953 B 1 Frequently Asked Questions The message Error writing configuration has appeared What should I do This message is most commonly displayed when there is no 12V power source to the main logic board of the computer system Newer systems have 3 3V connectors as well and occasionally the 12V line is not attached to the board Check your internal power connectors first There may also be a problem with the Non volatile RAM NVRAM or the EEPROM on the controller The configuration is written to both of these memories If you re
66. ent Administering the Array describes the tasks that can be done to the array after it has been placed in service This includes array tuning recovery after a power failure management of the array after a hardware malfunction tools and diagnostics For information on setting the controller s SCSI termination jumpers and connecting the disk drives consult the appropriate DAC960 Series Disk Array Controller Installation Guide Conventions Throughout the manual the following conventions are used to describe user interaction with the product bold the user must enter the bold text exactly as shown a press the Enter key Enter press the key labeled Enter or Delete etc File Run select the Run option from the pull down menu activated when the File menu pad is selected Note Supplementary information that can have an effect on system performance Caution Notification that a proscribed action has the potential to adversely affect equipment operation system performance or data integrity WARNING Notification that a proscribed action will definitely result in equipment damage data loss or personal injury Contents Chapter 1 Introduction to DACCF OVOrVIOW gode Pay de te a ea es 1 1 Whatis DAGCE o aia ar de vx da quieres 1 1 When to Use DACCF 1 2 Howto Use DAGGF psio de ueta sata male som hr e RR 1 2 Functions Provided by DACCF 1 3 C
67. er The default mode setting is Automatic Automatic This spin up mode causes the controller to spin up all con nected drives two at a time at six second intervals until every drive in the array is spinning The controller then interrogates each drive one at a time at six second intervals and confirms that the drive is ready for use The interrogation process repeats until all drives have been verified 4 38 DACCF Utilities Administering the Array On Power This spin up mode assumes that all drives are already spinning and proceeds to interrogate the drives in the same manner as described for Automatic mode On Command This spin up mode causes the controller to wait for a spin up command from the host It then proceeds to spin up the drives in the same manner as described for Automatic mode Number of Devices Per Spin Specify the number of drives to spin up Values range from 1 to 6 Delay After the controller completes its initialization process the delay value defines the number of seconds before the first disk interrogation request is issued to the array Delay values range from 0 to 30 in six second increments Manual No 771953 4 39 Administering the Array Device Management From time to time you may have to manage individual physical devices in your array This includes removing and replacing disk drives and ensuring that the controller keeps track of these operations For example a drive that has failed may need
68. ering the Size of the System Drive 3 30 DACCF Utilities Preparing the Array 6 A window with a summary of this system drive s settings and a confir mation dialog box is presented Figure 3 31 MYLEX Disk Array Controller Configuration Utility Version n nn nm dd yy n Channel nn Target DACI6HXX tn Firmware version n m Pak Drus Size MB System Drive Definition 1 Create System Drive 2 Toggle Write Policy A 3 3039 System Drivel 4 Raid Level Capacity 5 Sys Dru Size MB RAID Write Mode 2626 ME Do you want to Create this System drive 7 NO EEUU GENE Dose D Due e O on D E Figure 3 31 System Drive Summary Select YES to create the system drive and add it to the System Drive Table The drive is added to the table and control is returned to the System Drive Definition menu Select NO to cancel the creation of the system drive and return to the System Drive Definition menu 7 Repeat steps 2 through 6 to create additional system drives Note Several arranged groups can be included in a single system drive if each of the arranged groups has the same number of drives This is known as spanning a system drive across drive groups and is automatically configured when the size of the system drive is entered Manual No 771953 3 31 Preparing the Array
69. et aside one available drive to be used as a hot spare before all other drives are configured Select NO to choose not to set aside a hot spare Automatic Configu ration will use all available drives to create the current configuration 5 Next select the write policy for the system drive that is to be automati cally created Figure 3 17 MYLEX Disk Array Controller Configuration Utility Version n nn nn dd uy n Channel nn Target DACI66XX tn Firmware version n m Automatic Configuration Do you want to have Write Cache enabled 7 YES Figure 3 17 Selecting the Write Policy Select NO to set the write policy of the system drive to write through 3 18 DACCF Utilities Preparing the Array Select YES to set the write policy to write back Note A write back policy which stores data in the cache temporarily during a write operation will result in better performance at the expense of potential fault tolerance In the event of a power failure any data in the cache will be lost unless the cache has a battery backup A write through policy which writes data to the disk AND cache will result in lower performance but no data can be lost in the event of a loss of power For more information about write policies refer to the Glossary Mylex strongly recommends the use of a bat tery backup option or an uninterruptable power sup ply UPS with any disk array configured with the
70. eter below select Startup Parameters from the Edit View Parameters menu Figure 4 38 MYLEX Disk Array Controller Configuration Utility Version n nn nn dd uy n Channel nn Target DACI66XX tn Firmware version n m Edit Uieu Parameters Harduare Paraneters Physical Paraneters SCSI Xfr Parameters Startup Parameters Choose this option to view or edit the controller s changeable Disk drive spinup options Figure 4 38 Startup Parameters Option Manual No 771953 4 37 Administering the Array The Start up Parameters menu appears Figure 4 39 MYLEX Disk Array Controller Configuration Utility Version n nmn nn dd uy n Channel nn Target DACIGBXX iin Firmware version n m Start up Parameters Spin up option Automat ic Number of devices per spin 2 Delay seconds 6 Figure 4 39 Start Up Parameters Menu To change a parameter do the following 1 Highlight the desired parameter using the cursor keys 2 Press the Enter key to change the value 3 When the correct value is displayed either Repeat steps 1 amp 2 above but for a different parameter or Press the Esc key to return to the Advanced Functions menu The change will be retained Spin Up Option The Spin up function controls how the SCSI drives in the array are started spun up There are three different Spin up modes that may be selected by the us
71. f a redundant drive group and is in the process of being rebuilt from data and or parity on other drives in the drive group UNF Disk needs to be low level formatted TAP Device is a tape drive and will not be included in any DACCF operations CDR Device is a CD ROM drive and will not be included in any DACCF operations 3 22 DACCF Utilities Preparing the Array 5 Press the Enter key to include it as part of the drive group When a disk is selected for inclusion in a drive group a pack identifier A B C and disk index 0 1 2 are assigned and the disk status changes to ONL Figure 3 23 MYLEX Disk Array Controller Configuration Utility Version n nn mmddyy n Channel nn Target DACI66XX tn Firmware version n m Tgt Channel Number Pack Definition ID 1 i 1 Create Pack E Eg Z Cancel Pack RD 3 Pack L p Bo Jom RD Aa pg ME 223 PAK DRUS SIZE MB 3 E CA 0 lt 4 Co 25 Co 31 r Figure 3 23 Devices with pack identifiers assigned 6 Repeat the previous two steps for as many drives as you want to include in a single drive group Note Drive groups can include disks on different channels if the array has multiple channels and disks are con nected to each channel The number of drives in a drive group will determine the allowable RAID levels for all of the system drives created in that drive group No more than ei
72. fine Pack 2 Define System Drive Choose this option to view existing packts OR create arrange cancel one or more additional packs Figure 4 2 View Update Configuration Menu Use this option to make additions to the configuration while retaining the existing configuration and any data that is resident on system drives in the existing configuration The following functions are available e Change the write policy of any system drive from write back to write through and vice versa The write policy can be changed at any time e Create new standby drives If new physical drives are being added they can be designated as standby drives e Create new drive groups and system drives Existing standby drives and new physical drives can be assigned to new drive groups for subsequent use in the definition of system drives e View the existing configuration All array information including drive groups arranged groups system drives RAID levels and write policies for system drives is displayed Note Existing drive groups and system drives cannot be changed by using this function 4 2 DACCF Utilities Administering the Array Changing the Existing Write Policy To change an existing system drive s write policy do the following 1 Select Define System Drive from the View Update Configuration menu The System Drive Definition menu Figure 4 3 will appear MYLEX Disk Array Controller Configu
73. from the bootable floppy for example update the CONFIG SYS file to include the line device a aspixxxx sys where xxxx identifies the particular ASPI device driver you have Manual No 771953 1 5 Introduction to DACCF 1 6 DACCF Utilities Chapter 2 Configuration Strategies Overview The information in this chapter is designed to help you choose the right con figuration for your disk array It introduces the following e Some disk array applications e The essential RAID terms and techniques you will need to know e The CAP strategy for selecting the best possible configuration e Tables to help you match RAID levels to available drives Understanding the CAP strategy will help you to achieve your storage goals to maximize storage Capacity to assure data Availability to provide the best possible I O Performance or to utilize combinations of the three What s the Purpose of Your Array That s the first question you ll need to ask yourself before you start prepar ing to configure your array Will you be using the array to increase the capacity of your general purpose file and print server Will you be using it to support a database application that has to keep running 24 hours a day Is the array going to contain large files of audio or video clips that can be played back on demand Is the array going to be used as a repository for imaging systems What is the Data Access Profile Each of the above applications has
74. g to just the physical devices Up to eight 8 drives can be configured together as one drive group All the physical devices in a drive group should have the same size other wise each of the disks in the group will effectively have the capacity of the smallest member The total size of the drive group will be the size of the smallest disk in the group multiplied by the number of disks in the group For example if you have 4 disks of 400MB each and 1 disk of 200MB in a pack the effective capacity available for use is only 1000MB 4 200 not 1800MB G 2 DACCF Utilities Glossary Hot Replacement of Disks Hot Swap The design of the DAC960 Series controllers allows for the replacement of failed hard disk drives without interruption of system service In the event of a SCSI drive failure on a properly configured system where the data redundancy features of the controller are used system service continues without interruption message is generated by the system to alert the system operator When a replacement drive becomes available the system operator can remove the failed disk drive install a new disk drive and instruct the con troller to rebuild the data on the new drive all without interrupting system operations Once the rebuild is complete the controller will be brought back into a fault tolerant state Logical Drive States The state of a logical system drive can be either ONLINE CRITICAL or OFF
75. ght physical drives can be included in a drive group To use more than eight drives create two groups that have an equal number of physical drives Then arrange the drive groups Arrange the Drive Groups on page 3 25 to use both drive groups in a single system drive 7 To finish creating a drive group press the ESC key The device high lights disappear but the pack identifier and disk index for each selected device remain Figure 3 24 Y ou will return to the Pack Definition menu Manual No 771953 3 23 Preparing the Array MYLEX Disk Array Controller Configuration Utility Version n nn nn dd uy n Channel nn Target DACIGBXX tn Firmware version n m Tgt Channel Number Pack Definition ID a8 1 1L p dde to as i pe Us 13 PAK DRUS SIZE MB a EA ET ET ET ER Co Press FZ to View full Display Figure 3 24 After creating a drive group 8 Repeat steps 4 7 for as many drive groups as you wish to define Toreserve a disk as a hot spare do not include it in any packs Select Cancel Pack from the Pack Definition menu to release the drives in a pack highlight any drive in the pack to be released and press the Enter key 9 When you have finished defining drive packs press the ESC key to return to the Pack Definition menu Note If you have included all of the physical drives into a single drive group the drive group will be automat
76. guration H3 View Update Configuration B4 Rebuild BS Initialize System Drive B6 Consistency Check B7 Tools HB Select DAC96H B3 Advanced Functions 18 Diagnostics If 3 or more Physical drives are present choose this option to create one R ID 5 System drive automatically Overview The DACCF software tools are located on the DAC960 Configuration amp Utilities diskette that is supplied with all Mylex DAC960 Series Disk Array Controllers What is DACCF DACCF is an acronym for the Disk Array Controller ConFiguration utili ties It is a set of MS DOS compatible programs used to configure initialize and manage RAID Redundant Array of Independent Disks subsytems con nected to a Mylex DAC960 Series controller DACCF utilities provide the necessary software tools needed to get the disk array up and running as well as advanced functions for monitoring control ling and managing DAC960 Series controllers and their connected disk array subsystems Manual No 771953 1 1 Introduction to DACCF When to Use DACCF You should use DACCF utilities e To configure and initialize an array during initial system setup before loading the operating system e To save the array configuration information to a disk file e To periodically monitor the state of various devices within an array e To verify disk integrity after a power failure to an array by running a consistency check e To take drives on li
77. h noting In the section of the configuration report entitled Physical Pack Information a line reading Pack O 1 0 1 1 1 2 Indicates that three physical drives are part of the first drive group in the array e These physical drives are all located on controller channel 1 and have SCSI ID s of 0 1 and 2 respectively e Furthermore the drives were added to this drive group in the order in which they are listed from left to right In the example above the drive with SCSI ID 0 was added first followed by the drive set to SCSI ID 1 followed by the drive with SCSI ID 2 In the section of the configuration report entitled System Drive Information the column Phy Size refers to the amount of space on the physical drive group which is occupied by a particular system drive The column Eff Size refers to the capacity of the system drive as presented to the operating system with RAID levels taken into account In most cases the numbers will be different with the Eff Size being the lesser of the two values 4 26 DACCF Utilities Administering the Array Advanced Functions To facilitate tuning of the array for optimal performance a number of con troller settings as opposed to the array configuration stored in the control ler s memory can be changed These controller settings or parameters are accessed by selecting the Advanced Functions option on the Main menu Figure 4 28 MYLEX Disk Array Contr
78. i cally arranged and the System Drive Definition menu will appear as shown in Figure 3 28 If this is the case proceed to Defining and Creating a System Drive on page 3 27 Change or Cancel a Drive Group To change a drive group you must first delete the drive group and then re create the group To delete a drive group select Cancel Pack from the Pack Definition menu 3 24 DACCF Utilities Preparing the Array Note You can only cancel the most recently created drive group This means that if you ve defined three drive groups and then decide that you want to change the contents of the first drive group you ll have to delete all three groups the current or third group then the second group and finally the first group Before delet ing any drive groups though you may want to write down the contents of the drive groups that you do not want to change When you ve changed the first group you can then quickly recreate the second and third groups from your notes Create a Standby or Hot Spare disk To create a standby or hot spare drive do not include the device as a part of any drive group The device status will change from RDY to SBY when the configuration is saved to memory Saving the configuration is explained later in this chapter Arrange the Drive Groups Next arrange the drive groups that you have created by selecting Arrange Pack from the Pack Definition menu The pack arrangement screen will be displayed
79. ical drive failure The Bad Block Table option lets you view the two tables that the DAC960 maintains during both a rebuild process as well as normal operation To view either or both of these tables select Bad Block Table from the Tools menu The View Bad Block Table menu appears Figure 4 41 MYLEX Disk Array Controller Configuration Utility Version n nn nn dd uy n Channel nn Target DACI6BXX tn Firmware version n m Tgt Channel Number ID B 1 Tools NL E B a 1 Bad Block Table NL 2 Error Counts 127 Cl 3 Format Drive BY NL 4 Make Online 2227 8 2 5 Kill Drive NL 6 Backup Restore conf 321 Gd 7 Clear Configuration 11 IE 1 B Print Configuration 4 NL 5 a C Mieu Bad Block Table NL LES C View Rebuild BBT View Write Back BBT Press FZ to View PuL Display Figure 4 41 View Bad Block Table Menu Note A bad block table is cleared after viewing Make sure that you record any information either by saving the table to another disk drive or by manually transcribing the information in the table View Rebuild BBT During a rebuild operation data is read from existing redundant drives in the drive group reconstructed by the controller and then written to the replacement drive If a read error on an existing drive occurs during a rebuild the process will fail In that case one of the existing drives not the replacement drive has e
80. icate when a device needs to be repaired or replaced Viewing the error counts for a particular device displays the number of errors in each table for the selected device 4 42 DACCF Utilities Administering the Array Error counters have the following properties A maximum of 127 errors can be recorded for each device in each table Error counters can be reset to O by power cycling the array controller Parity errors A count of the SCSI bus parity errors that occurred while this device was transferring information on the bus Soft errors A count of check condition errors reported by the device These errors are typically generated when a bad sector on the disk is encoun tered Such errors are recovered by the DAC960 if the device is part of a redundant system drive by generating the data from the remaining disks The bad sector on the device is also eliminated by writing back the data onto the disk and reading to verify since a verify failure results in the re assign ment of data to a different sector Soft errors may occur during normal oper ation if the device has bad sectors Hard errors Hardware related errors on the DAC960 controller The fol lowing conditions cause the hardware error count to be incremented for a device e SIOP interrupt for Illegal instruction detected e SIOP interrupt for Gross error e SCSI device executed illegal unsupported phase sequence During normal operation the hard er
81. ice startup parameters 4 37 initial delay 4 39 number of devices per spin 4 39 spin up option 4 38 Drive groups 2 6 arranging 2 7 3 25 assigning RAID levels to system drives 2 9 automatic configuration 3 15 changing or cancelling 3 24 creating 3 15 creating a standby or hot spare disk 3 25 device information 3 26 logical system drives 2 8 Index 1 Index matching RAID levels to available drives 2 9 new configuration 3 20 standby hot spare drives 2 8 E Error conditions D 1 Error counts 4 42 Exiting DACCF 3 39 F Frequently asked questions B 1 H Hardware parameters 4 29 automatic rebuild management 4 31 operational fault management 4 31 Host based DAC support files A 1 I Installing DACCF 1 5 adding SCSI to SCSI drivers 1 5 J Jump keys 3 3 L Logical sector size DAC960S Only 4 34 Low level formatting 3 10 M Main menu 3 4 Managing physical drives and SCSI devices 2 6 Managing the array 1 3 N Navigating within DACCF 3 2 cursor keys and jump keys 3 3 exiting a menu 3 4 selecting an item 3 4 using a mouse 3 4 New configuration 3 20 Index 2 O Opening screens 3 5 Overview 1 1 P Pack definition screen 3 21 Physical parameters 4 31 default rebuild rate 4 32 logical sector size 4 34 stripe size 4 34 super read ahead 4 33 Physical sector size DAC960S Only 4 34 Preparing the array 3 1 Print configuration 4 25 R RAID levels 2 2 assigning to system drives 2 9 matching to ava
82. ilable drives 2 9 JBOD RAID 7 2 5 RAID 0 2 3 RAID 0 1 RAID 6 2 5 RAID 1 2 4 RAID 5 2 4 selecting 2 3 supported 2 3 RAID levels and availability 2 14 RAID levels and performance 2 15 RAID rules 2 16 Rebuild drives 4 8 Restore a configuration 4 22 S Saving updated configuration 4 7 SCSI transfer parameters 4 34 command tagging 4 37 data transfer rate 4 36 SCSI data bus width 4 37 SCSI to SCSI DAC960 products support files A 1 Segment size 3 9 DACCF Utilities Selecting the DAC960 controller 3 7 Standby drives creating 4 5 Stripe Size 3 8 Stripe width 3 29 System drive defining and creating 3 27 initializing 3 34 saving the new configuration 3 33 toggling write policy 3 32 T Title window 3 2 Tools menu 3 10 V Viewing updating the configuration 4 1 Manual No 771953 Index Index 3 Index Index 4 DACCF Utilities
83. ilure occurs before the data in the cache is written to disk To avoid this potential loss of data at the very least you should outfit your controller with a battery backup module for the cache memory The battery backup option will enable the cache to be retained until normal operation resumes at which time the data in the cache can be written to the array Your data is most likely as important as your server probably much more so and this simple and inexpensive insurance can prevent a power interruption from turning into a disaster If the array controller is not and will not be configured to use Write Back cache then battery backup of the cache is not necessary If the write cache is used without the battery backup option installed on the DAC960 then an uninterruptible power supply also known as a UPS should be used with your disk array Manual No 771953 2 13 Configuration Strategies RAID Levels and Availability To see the relation between the different RAID levels offered by the DAC960 controller and the advantages and disadvantages of the RAID levels as they apply to availability refer to Table 2 5 Table 2 5 RAID Levels and Availability RAID Availability Level Fault tolerance 0 No fault tolerance Data is striped across a set of multiple disks If a disk in the set ceases to function all data contained on the set of disks is lost This configuration is not recommended if fault tolerance is needed 1
84. ilure or system crash Write Through Cache Refers to a caching strategy whereby data is written to the SCSI drive before a completion status is returned to the host operating system This caching strategy is considered more secure since a power failure will be less likely to cause loss of data However a write through cache results in a slightly lower performance G 10 DACCF Utilities Index A Advanced functions 4 27 Array configuration table 2 19 key points about 2 18 using 2 17 Automatic configuration 3 15 B Backup a configuration 4 18 4 20 Bad block table 4 41 C cache line size 3 9 4 33 Changing existing write policy 4 3 Command line arguments C 1 Command line parameters 3 5 Configuration management 4 17 Configuration strategies 2 1 Configuration utilities 1 3 Configuring the array 2 10 maximum availability 2 12 maximum capacity 2 11 maximum performance 2 15 RAID levels amp availability 2 14 Consistency check 4 12 Controller parameters stripe size 3 8 setting 3 8 Creating new drive groups and system drives 4 6 Cursor keys 3 3 Manual No 771953 D DACCF description 1 1 exiting 3 39 file list A 1 how to use 1 2 installing 1 5 requirements 1 4 when to use 1 2 DACCF functions configuration 1 3 initialization 1 3 DACCEF screen actions bar 3 2 device representations 3 3 help box 3 3 menus and dialog boxes 3 2 title window 3 2 Data Access Profile 2 1 Device management 4 40 tools 4 40 Dev
85. ine 2227 8 2 5 Kill Drive NL 6 Backupr Restore conf 3 E Gd 7 Clear Configuration L co B Print Configuration 4 NL 5 Co CA Enter File Name NL 6 mai 14 C gt dim Press FZ to View full Display gt Figure 4 27 Specify the Configuration Text File 2 Input the name of the file and press the Enter key The filename can be up to 10 characters including the drive prefix Avoid using full path names Mylex suggests that you name the file so that you can easily rec ognize it when you need it for example RAID TXT or ARRAY TXT 3 A confirmation box will appear Select YES to create the configuration text file The system will pause briefly while the configuration file is written A message at the bottom of the screen will display indicating successful creation of the file The resulting file will be written in ASCII text format which can be viewed or printed with a word processor or text editor To return to the Tools menu press any key Select NO to abort the creation of the configuration description file You will return to the Tools menu Manual No 771953 4 25 Administering the Array Mylex recommends that a printed copy of the output along with a diskette containing both the file that created the printed copy and a copy of the con figuration file created with the Backup Configuration utility be kept in a safe place While the output report is largely self explanatory a few items are wort
86. ing questions before configuring the array I have disks to be used in the array Rank the following statements in order of importance 1 2 and 3 I want to emphasize capacity I want to emphasize availability I want to emphasize performance Ihave channels on the array controller Usually 1 2 or 3 I plan to not to use a Hot Spare disk I do do not have a battery backup for the controller cache I do do not have a UPS for the array Using the Array Configuration Tables With all this to keep in mind for a given number of drives what should you do The tables on the following pages make some suggestions for configur ing from one to eight drives Use the tables as follows 1 Locate the number of drives you will use This starting point is in the first column of the table Drives and Drive Groups Remember to apply the RAID Rules to the configuration par ticularly when connecting drives to the controller 2 Determine how many drive groups you want Select from the example configurations for the number of drives that you have the DAC960 supports up to eight drive groups In the table each drive group is indicated by a letter A through H Use as few drive groups as possible to cover your needs Configured drives are indicated by o Drives that are not part of any drive group are indicated by o italicized and are available for use as standby drives 3 Select the RAID level Apply your CAP strategy and sel
87. ion I E CI r3 Ma pF 1 Figure 3 8 Format Drive Selected Manual No 771953 3 11 Preparing the Array 3 Select the drive to format by moving the highlight cursor to the desired drive and pressing the Enter key Figure 3 9 MYLEX Disk Array Controller Configuration Utility Version nem nndd yy n Channel nn Target DACIGBXX tn Firmware version n m Tgt Channel Number ID 6 1 Tools RDY aL C 1 Bad Block Table RD Y 2 Error Counts id CD RD RD 4 Hake Online 201 EE 5 Kill Drive RD 6 Backup Restore conf 3L C Y Clear Configuration NE Ll 8 Print Configuration 4 EE L 31 A11 DATA will be LOST emg LI Proceed with Format 7 6 YES Figure 3 9 Selecting a Device to be Low Level Formatted 4 A dialog box confirming the format operation will appear Select YES to include the drive in a format operation and press the Enter key The confirmation box will clear and the drive state will change to FMT Figure 3 10 Select NO to exclude a drive which has been selected for formatting 3 12 DACCF Utilities Preparing the Array MYLEX Disk Array Controller Configuration Utility Version n nn nn dd uy n Channel nn Target DACI6BXX tn Firmware version n m Tgt Channel Number ID B 1 Tools aC p 1 Bad Block Table DU EI RES 3273 7 Clear Configuration aL EI 8 Print Configu
88. is updated this error message may appear the first time DACCF is run after the update process To eliminate the condition 1 Save the default configuration Power cycle the array Reboot the computer 2 3 4 Rerun DACCF 5 Restore the configuration from a diskette containing a copy of the previ ously saved configuration Errors Which Cause a Drive to be Killed There are multiple conditions which will cause the DAC960 to kill or deactivate a drive from read write operations They are as follows SCSI Sequence Error Whenever a device follows an illegal SCSI phase sequence i e an unex pected disconnect the controller resets the SCSI bus and then interrogates all of the drives it expects to be there If all the drives respond properly operation continues If any drive fails to respond the controller kills that drive SCSI Busy Status When a drive gives the controller a BUSY response the controller retries the command If the count of BUSY responses from a drive exceeds a pre set value currently set at 48 the drive is killed Timeout on a Command If a drive does not complete a command issued to it within a pre set timeout period currently set at six seconds the DAC960 resets the SCSI bus inter rogates the drive and kills it if the interrogation fails The timeout condition also applies to drives that hold the SCSI bus for a long period Manual No 771953 D 3 DACCF Error Conditions Media Err
89. ive groups are iden tified alphabetically A through H by the DACCF utilities From one to eight drives can be included in an individual drive group The number of drives in a drive group determines the possible RAID level The following illustration shows a single drive not included in any drive group and two drive groups A and B each with three drives DAC960 OO 2 6 DACCF Utilities Configuration Strategies Arranging Drive Groups After drive groups have been created they need to be arranged Arranging drive groups provides a means to further organize the array For example Drive Group B in the previous illustration can be arranged to be the first drive group on the controller This would permit the creation of a primary system drive on Drive Group B that could function as a boot drive By sequentially arranging two drive groups with an identical number of disk drives each drive group s capacity is combined or spanned creating a Super Drive Group Such arrangement is done automatically by the DAC960 controller when two drive groups with an identical number of disks are arranged one after another Data is striped across the drive groups of the Super Drive Group irrespective of how data is distributed across the indi vidual drive group A system drive can span across up to four 4 drive groups Arranging drive groups so that a pack with a different number of drives is in between two groups of e
90. k Array Controller Configuration Utility Version nem nn dd uy n Channel nn Target DACI66XX tn Firmware version n m Save altered controller configuration 7 YES Figure 4 30 Save Controller Parameters Confirmation Select YES to save the new parameter settings The parameters will be saved and you will return to the Main menu Select NO to retain the parameter settings in effect before the Advanced Functions menu was entered Any changes made will not be applied and you will return to the Main menu Press the Esc key to return to the Advanced Functions menu 4 28 DACCF Utilities Administering the Array WARNING Many of the advanced functions can put any data stored on the array at risk if not delete it altogether Such functions are noted in the manual but Mylex recommends that you perform the modifications afforded by the advanced functions on an array that has not been loaded with a file system and data Additionally inappropriate changes to the controller parameter settings can result in degraded performance Hardware Parameters Hardware parameters control specific DAC960 functions To change any of the hardware parameters below select Hardware Parameters from the Edit View Parameters menu Figure 4 31 MYLEX Disk Array Controller Configuration Utility Version n nn nndd yy n Channel nn Target DACI66XX tn Firmware version n m Edit Uieu
91. key A confirmation box Figure 4 23 will appear MYLEX Disk Array Controller Configuration Utility Version n nn nn dd uy n Channel nn Target DACIGBXX fn Firmware version n m Tgt Channel Number ID 6 1 Tools NL aL Crad 1 Bad Block Table NL 2 Error Counts 1273 Cid 3 Format Drive BY NL 4 Make Online A p 2 5 Kill Drive NL 6 Backup Restore conf ql mse Y Clear Configuration NE Ll 8 Print Configuration 4 NL s E gl C Existing File if any NL Ll will be overwritten t 6 Hi I YES Figure 4 23 Backup Confirmation Select YES to proceed with backup of the configuration The configuration will be copied to disk WARNING If a file of the same name already exists on the target drive it will be overwritten with the new configuration Select NO to cancel the backup of the configuration You will return to the Backup Restore Conf menu Manual No 771953 4 21 Administering the Array Restore Configuration 1 Select the Restore Configuration option from the Backup Restore Conf menu to restore a configuration to the array from a configuration file on a diskette You ll be prompted to specify the name and location of the file containing the new configuration Figure 4 24 The filename can be up to 10 characters including the drive prefix Avoid using full path names Enter the name of the file and press the Enter key MYLEX
92. ly a rebuild operation will also be supported by Mylex utilities for various operating systems and as such this DACCF option may not have to be used To rebuild a physical drive do the following 1 Select Rebuild from the Main menu Figure 4 7 MYLEX Disk Array Controller Configuration Utility Version n nn nn dd uy n Channel nn Target DACI6BXX tn Firmware version n m Main Menu 41 az B3 B4 B5 46 a7 BB 49 16 Automatic Configuration Heu Configuration Vieu Update Configuration Rebuild Initialize System Drive Consistency Check Tools Select DACI64 Advanced Funct ions Diagnostics Choose this option to rebuild a replaced DE D physical drive The replaced physical drive should have been connected and powered on before invoking this Utility for the rebuild to take place Figure 4 7 Rebuild Option 4 8 DACCF Utilities Administering the Array 2 The rebuild screen will be displayed with the drive matrix on the left side of the screen Figure 4 8 MYLEX Disk Array Controller Configuration Utility Version nem nndd yy n Channel nn Target DACI6HXX tn Firmware version n m REBUILD Tgt Channel Number 1 Ci EU e A CU JUL Ul Figure 4 8 Drive Rebuild Screen 3 Using the cursor keys select the drive to be rebuilt Normally the drive to be rebuilt will be indicated by the letters DED for D
93. m Hain Menu Automatic Configuration Neu Configuration Mieu Update Configuration Rebuild Initialize System Drive B6 47 HB 49 16 Consistency Check Tools Select DAC96H fiduanced Functions Diagnostics Choose this option to perform special operations like lou level format of physical drive s backup restore print and clear the existing configuration Figure 4 19 Tools Option 4 18 DACCF Utilities Administering the Array 2 Select Backup Restore conf from the Tools menu Figure 4 20 MYLEX Disk Array Controller Configuration Utility Version nem nn dd uy n Channel nn Target DACIGBXX tn Firmware version n m Tgt Channel Number ID A 1 Tools aL Ced 1 Bad Block Table Y Gi 5 Format Drive L1 D diodes I 3 4 Ll 8 Print Configuration EI Co This option enables you to backup or restore the configuration to or from a file Exercise caution in using this option Figure 4 20 Configuration Management Warning 3 A message warning you to exercise caution when using this utility will appear Press any key to continue 4 The Backup Restore Conf Configuration menu appears in the lower right corner of the screen Figure 4 21 MYLEX Disk Array Controller Configuration Utility Version n nn nndd yy n Channel nn Target DACIGBXX tn Firmware version n m Tg
94. mplement several different versions of the Berkeley RAID technology and some other special versions that are specific only to the DAC960 product family Each RAID version referred to as a RAID level supported by the DAC960 is shown in the table on the next page An appropriate RAID level must be selected when system drives are defined or created This decision is based on the following priorities Disk capacity utilization number of drives Data redundancy fault tolerance Disk performance DAC960 Series controllers make the RAID implementation and the disks physical configuration transparent to the host operating system This means that the host operating system drivers and software utilities are unchanged regardless of the RAID level selected 2 2 DACCF Utilities Configuration Strategies Selecting the Right RAID Level Selecting the proper RAID level for a specific data storage application requires that consideration be given to the benefits of each technique RAID 0 Striping The controller stripes data across multiple drives Benefits Very high data throughput especially for large files Drawbacks Does not deliver any fault tolerance All data is lost if any drive in the array fails Uses Intended for non critical data requiring high performance Drives Minimum 2 Maximum 8 Table 2 1 DAC 960 Supported RAID Levels RAID Level Description 0 Block striping is provided which yields higher perfo
95. n a rebuild state While it is in the process of being rebuilt During this process data is regen erated and written to the disk drive This state is also referred to as Write Only WRO Segment Size The Segment Size function available in DAC960 firmware version 2 6 and above is set in conjunction with stripe size and represents the size of the data chunk that will be read or written at one time Under DACCF the segment size also known as cache line size should be based on the stripe size you selected See Table 3 1 in Chapter 3 for the available segment size settings to use for each stripe size The default segment size for Mylex DAC960 controllers is 8K Session Refers to the period of time between any two consecutive system shutdowns System shutdown may be either a power off on or a hardware reset Standard Disk Drive This term refers to a hard disk drive with SCSI IDE or other interface that is attached to the host system through a standard disk controller Standby Replacement of Disks Hot Spare The Standby Replacement or Hot Spare is one of the most important features the controller provides to achieve automatic non stop service with a high degree of fault tolerance The rebuild operation will be carried out by the controller automatically when a SCSI disk drive fails and both of the fol lowing conditions are true e A standby SCSI disk drive of identical size is found att
96. ne or off line during a drive replacement operation e To perform diagnostics on an array controller e To obtain specific information about a device in an array e To reconfigure and otherwise tune an array for optimal performance and availability WARNING Reconfiguring logical drives on an existing array will result in data loss Make sure that all data is backed up on different media before performing this task How to Use DACCF Describing how to use DACCF is similar to answering the question How do you awaken an 800 pound gorilla That is Very carefully While DACCF provides many safety prompts that alert you when you are about to take an action that can affect data or drive status you should be aware from the outset that DACCF is meant to be used only by persons with Manager or Supervisor rights These are powerful utilities that must be used properly or data loss can result You should not have a problem however if you follow the instructions in this manual observing any Notes Cautions and Warnings before performing an operation In addition it is a good idea to have a written plan that identifies the system resources e g devices capacities locations by SCSI channel target ID etc and the desired logical drive configurations LUN sizes RAID types etc before you begin setting up or changing an array configuration 1 2 DACCF Utilities Introduction to DACCF Functions Provided by DACCF Config
97. ning on the controller checks among other things elapsed time on all commands issued to disks A time out causes the disk to be reset and the command to be retried If the command times out again the disk could be killed taken offline by the controller its state changed to dead DAC960 Series controllers also monitor SCSI bus parity errors and other potential problems Any disk with too many errors will also be killed Disk Media Error Management DAC960 Series controllers transparently manage SCSI disk media errors Disks are programmed to report errors even ECC recoverable errors When a disk reports a media error during a read the controller reads the data from the mirror RAID 1 or 0 1 or computes the data from the other blocks RAID 5 and writes the data back to the disk that encountered the error If the write fails media error on write the controller issues a reassign command to the disk and then writes the data to a new location Since the problem has been resolved no error is reported to the system When a disk reports a media error during a write the controller issues a reassign command to the disk and writes the data out to a new location on the disk Drive Groups or Drive Packs A group of individual disk drives preferably identical that are logically tied to each other and are addressed as a single unit In some cases this may be called a drive pack when referrin
98. of a sequential block of incoming data across multiple SCSI drives in a group For example if there are 3 SCSI drives in a group the data will be separated into blocks and block 1 of the data will be stored on SCSI drive 1 block 2 on SCSI drive 2 block 3 on SCSI drive 3 block 4 on SCSI drive 1 block 5 on SCSI drive 2 and so on This storage method increases the disk system throughput by ensuring a balanced load among all drives System Drives A system drive is equivalent to a logical drive System drives are pre sented to the operating system as available disk drives each with a capacity specified by the DAC960 Series controller Target ID A target ID is the SCSI ID of a device attached to a DAC960 Series controller Under firmware versions below 2 6 each SCSI channel can have up to 7 attached SCSI devices target ID from 0 to 6 Under firmware versions at or above 2 6 each SCSI channel can have up to 15 attached SCSI devices target ID from 0 to 6 and 8 to 15 Manual No 771953 G 9 Glossary Write Back Cache Refers to a caching strategy whereby write operations result in a completion signal being sent to the host operating system as soon as the cache not the disk drive receives the data to be written The target SCSI drive will receive the data at a more appropriate time in order to increase controller perfor mance An optional cache battery backup can be used to protect against data loss as a result of a power fa
99. oller Configuration Utility Version n nmn nn dd uy n Channel nn Target DACIGBXX tn Firmware version n m Hain Menu Bi Automatic Configuration BZ New Configuration H3 View Update Configuration B4 Rebuild BS Initialize System Drive B6 Consistency Check B7 Tools HB Select DAC96H 18 Diagnostics Choose this option to vieu or edit controller configuration parameters Figure 4 28 Advanced Functions Option When selected the Edit View Parameters menu appears Figure 4 29 MYLEX Disk Array Controller Configuration Utility Version n nn mmddyy n Channel nn Target DACIGBXX tn Firmware version n m Edit Vieu Parameters arduare Parameters Physical Parameters SCSI Xfr Paraneters Startup Parameters Choose this option to vieu or edit the controller s changeable Hardware features like battery backup Figure 4 29 Edit View Parameters Menu Manual No 771953 4 27 Administering the Array Note Different Mylex adapters support different Advanced functions Not every function listed below may be available to your controller Any changes to controller parameters from the Advanced Functions menu or one of its sub menus can be saved when exiting the Advanced Functions menu To exit the Advanced Functions menu do the following 1 Press the Esc key A confirmation box will appear Figure 4 30 MYLEX Dis
100. ompletely over write the contents of the current configuration Therefore any data residing on the array when the new configuration is implemented will be at risk Use this option with caution and then only after the current configuration has been saved to disk as well The new configuration will be in effect when the controller is reset or the array is next power cycled Select NO to cancel the restoration of the configuration You will return to the Backup Restore Conf menu Note Youcan only restore configurations with files that were created by the Backup Configuration option If a configuration file is created by other means and then used in a restoration unpredictable array behavior will result Clear Configuration Use the Clear Configuration option to erase an existing DAC960 configu ration from memory All drive groups system drives and RAID levels will be cleared Any controller settings hardware parameters will remain unchanged WARNING Any data on system drives will be lost when the configuration is cleared and a new configuration is created Use this option with extreme caution and ensure that you have made a backup of the configuration before clearing the configuration Manual No 771953 4 23 Administering the Array To clear a configuration follow these steps 1 Select Clear Configuration from the Tools menu The Clear Configura tion confirmation Figure 4 26 will be displayed MYLEX Disk Array
101. onfiguration NL E 1 3 Initialization oo xo med Rea A AA 1 3 Managing the Array 1 3 Diagnostic and Configuration Utilities 1 3 DACCF Requirements 1 4 Hardware pata pret Aan EXER ROLE ete dur Ae RR EH DEOR HO Eb O 1 4 SO tWate betes Ren Ip We Pep velo idc Va ese 1 4 Installing DAGGFP coo oet ra er Pre epi eM p vd eg 1 5 Procedure oec tpe UR PUE PR PUDE PI A Ee 1 5 Adding SCSI to SCSI Drivers 1 5 Chapter 2 Configuration Strategies uM LEE 2 1 What s the Purpose of Your Array 2 1 What is the Data Access Profile 2 1 RAID Essentials for DAC960 Series Controllers 2 2 Selecting the Right RAID Level 2 3 RAID 0 Stilping e ea eae Ev RIED wee ge 2 3 RAID 1 Mirroring iee o a RII I eem 2 4 RAID 5 Striping with Parity 2 4 RAID 0 1 Mirroring and Striping 2 5 JBOD Single Drive Control 2 5 Managing Physical Drives and SCSI Devices 2 6 Drive Groups Mor evens aude A lie ats 2 6 Arranging Drive Groups 2 7 Standby Hot Spare Drives 2 8 System Logical Drives
102. ons below 2 6 or 2TB terabytes when using firmware versions 2 6 and above Up to eight 8 system drives can be created per controller with DAC960 Firmware versions below 2 6 up to 32 system drives for firmware 2 6 and above Each system drive has a RAID level which is selectable subject to the number of disks in the system drive s drive group A system drive has selectable write policy write back or write through Manual No 771953 3 27 Preparing the Array Creating a System Drive To create a System drive follow these steps 1 Select Define System Drive from the New Configuration menu Figure 3 27 MYLEX Disk Array Controller Configuration Utility Version n nn nndd yy n Channel nn Target DACI66XX tn Firmware version n m Neu Configuration 1 Define Pack 2 Define System Drive Choose this option to create Systen drives of a particular RAID level capacity and write policy Figure 3 27 New Configuration Define System Drive The System Drive Definition menu Figure 3 28 will appear This screen displays the existing arranged drive groups System Drive Definition menu and System Drive Table which should be empty as there are no defined system drives As system drives are defined entries are added to this table MYLEX Disk Array Controller Configuration Utility Version n nn nn dd uy n Channel nn Target DACIGBXX iin Firmware ve
103. ons that are not possible or that are forbidden Help text is displayed brighter than normal dialog box text and is framed by a double line box Getting Around Within DACCF Cursor Keys and Jump Keys DACCF makes extensive use of the cursor movement keys on your key board these are sometimes called arrow keys and are labeled as en on the keyboard for menu navigation These keys position a highlighted bar called the cursor on various items or objects of interest If there are multiple possi ble selections available for a specific function that you want to perform the cursor will only move between the valid choices skipping all the invalid choices An alternative and faster method of positioning the cursor while in a menu is via the Jump keys The jump key for any menu item is the single num ber or character which is displayed brighter than the surrounding text for that item In the example shown in Figure 3 2 the jump keys are A N V R I C T S F and D or 01 10 When presented with any menu type the jump key associated with a particu lar item to move directly to the item The jump keys are case insensitive Manual No 771953 3 3 Preparing the Array Firmware versions above 2 6 allow for up to 15 target devices per channel while versions at or below 2 6 allow for up to 8 target devices per channel This difference is reflected in the number of target IDs available in the left hand window Use F2 followed b
104. or Recovery Flow If a drive reports a media error on a read command the DAC960 recon structs the data from the mirror or from parity and data on other drives It then writes the data to a different area of the disk to clean the error if pos sible The data is read from the new location for verification If the read of the data at the new location fails the DAC960 issues a reassign to the drive selecting another new location and then repeats the write verify operation A reassign failure or two successive failures in verification will result in the drive being killed Interrogation Sequence Start Drive During the drive startup sequence the DAC960 issues several SCSI com mands Inquiry TUR Sync negotiation and when supported Wide negotia tion Following these commands the DAC960 issues a read command on a reserved block of the drive The timeout for all of these commands is three seconds If any error including timeout is encountered during the interroga tion sequence the drive is killed The interrogation sequence is performed for each drive every time an error occurs on the bus which requires a SCSI Reset Operator Command A drive can also be killed via DACCF or via a Mylex utility for a specific operating system D 4 DACCF Utilities Glossary Bad Block Table or Bad Data Table There are two bad block tables that the controller automatically maintains The Rebuild Bad Block Table stores information on
105. qual number drives will prevent this spanning fea ture from being enabled Another simple way to prevent automatic spanning is to completely finish arranging a drive group defining its RAID level and system drives and initializing the array before continuing on with creating another drive group that contains the same number of drives In the following illustration a Super Drive Group on the left has been cre ated with the effective capacity of six disk drives because the drive groups with three drives each are arranged sequentially In the example on the right three unspanned drive groups have been created two groups of three drives and one group of two drives SPANNED NOT SPANNED o L Super Drive Group Individual Drive Groups Manual No 771953 2 7 Configuration Strategies Standby Hot Spare Drives Drives that are not included in any drive group at the time of configuration with DACCF are automatically used by the DAC960 controller as standby or hot spare drives DACCF denotes standby drives as SBY There is no limit on the number of available drives that can be configured as standby drives Two arranged packs and a standby drive are shown in the following illustra tion Notice that what is being illustrated is how the controller is organizing the drives since the cabling scheme depicted in this configuration is the same as the one shown in the first illustration The physical capacity of the
106. r expectations of the disk array subsystem What is your best strategy for configuring the array Do you want to access the maximum capacity of your disk drive investment Or do you want to configure your array for a high degree of fault tolerant operation Perhaps performance is extremely important to you Every installation has a different set of requirements and most installations have a combination of these Unfortunately it isn t possible to configure an array with all of these charac teristics optimized that s a limitation of the technology as they re some what mutually exclusive For example you can t have maximum capacity and maximum availability in a single array Some of the disks have to be used for redundancy and in doing so capacity is reduced Similarly configuring a single array for both maximum availability and maximum performance is not an option 2 10 DACCF Utilities Configuration Strategies You will need to make compromises Luckily your DAC960 Series control ler is versatile enough to offer you any of these preferences either singly or in the most favorable combination possible It comes down to this you will need to decide which capability is most important for your operational environment and which is next most impor tant Once you ve prioritized your expectations it should be relatively easy to configure the array to meet your expectations Configuring for Maximum Capacity You may want to optimiz
107. r s memory doesn t agree with the state of the drives as reported by the DAC960 BIOS during power up Manual No 771953 D 1 DACCF Error Conditions MYLEX Disk Array Controller Configuration Utility Version n nmn nn dd uy n Channel nn Target DACI66XX tn Firmware version n m Automatic Configuration Automatic configuration FAILED as all drives are not of the same size OR the number of drives is less than 3 or greater than 8 Figure D 1 Installation Abort Message To fix this condition 1 2 Ensure that all devices are connected powered on and functioning properly Reboot the computer system If the problem persists do the following 1 2 D 2 Rerun DACCF When the error message is displayed press any key A summary of the state of the devices will be displayed To save the setup press the S key The configuration will be saved and you ll be returned to the Main menu To abort the automatic configuration process press the ESC key At this point you will need to turn off power to the array and to the com puter and either resolve the hardware problem by adding or remov ing disk drives as necessary or decide to perform a manual configuration The computer and array must then be powered on and DACCF rerun Power cycle the array and the computer Rerun DACCF DACCF Utilities DACCF Error Conditions Configuration Checksum Error If the DAC960 s firmware
108. ransfer function sets the maximum transfer rate for each drive channel The default setting is 20M Hz This setting produces 10 MB sec transfers for Fast SCSI and 40 MB sec transfers for Wide and Ultra SCSI The default setting should be changed only if problems are encountered in communicating with a drive Do not change the default setting unless you are doing so as part of a troubleshooting activity 4 36 DACCF Utilities Administering the Array Note Problems communicating with a drive can be caused by several conditions e g improper termination wrong drive ID setting SCSI cable is too long faulty equipment etc Command Tagging Command tagging controls SCSI command tag queuing support for each drive channel This function normally remains enabled Disable only when using older SCSI drives not supporting command tag queuing SCSI Data Bus Width The Force 8bit Drive Channel function allows the controller to communi cate with Wide SCSI 16 bit devices connected to it through a Narrow SCSI 8 bit data cable on the specified drive channel Startup Parameters Device startup parameters affect the power consumption of the disk devices within the array A running drive consumes a fraction of the power necessary to start the drive To minimize the strain on the power supply of the array the drives can be started in sequence spreading the consumption of power out over a defined period of time To change any device startup param
109. ration C ra MAA Figure 3 10 Device Selected for Low Level Formatting 5 At this point steps 3 and 4 can be repeated for other disk devices in the array that should be included in the low level format 6 After all devices have been selected for formatting press the ESC key A confirmation box will appear Figure 3 11 MYLEX Disk Array Controller Configuration Utility Version n nn nndd yy n Channel nn Target DACIGBXX iin Firmware version n m Tgt Channel Number ID A 1 Tools RDY aL C 1 Bad Block Table RD Y 2 Error Counts L 3 CD FMT RD 4 Hake Online 201 E 5 Kill Drive RD 6 Backup Restore conf ql C Y Clear Configuration LI Ll 8 Print Configuration 4 FMT sJ C Do you really uant to CENT Ll FORMAT selected drives 6 I YES Press FZ to View full Display Figure 3 11 Device Format Confirmation Select YES to format the drives and press the Enter key The drive low level format process will commence Select NO to abort the format process and press the Enter key The Manual No 771953 3 13 Preparing the Array selected drives will not be formatted and you will return to the Tools menu 7 If a device cannot be low level formatted a message will appear Figure 3 12 indicating the channel and ID of the device The device should be replaced and the low level format process repeated for that device
110. ration Utility Version n nmn nndd yy n Channel nn Target DACI66XX tn Firmware version n m Pak Drus Size MB System Drive Definition AY 3 3439 1 Create System Drive BY 4 1316 Z Toggle Write Policy Sus Dru Size MB RAID Urite Mode B 2826 5 WRITE BACK 1 658 6 WRITE BACK Figure 4 3 System Drive Definition Menu 2 Select Toggle Write Policy from the System Drive Definition menu Figure 4 4 MYLEX Disk Array Controller Configuration Utility Version nem nndd yy n Channel nn Target DACI6HXX tn Firmware version n m Pak Drus Size MB System Drive Definition n 3 3439 1 Create Systen Drive BY 4 1316 2 Toggle Write Policy Sys Dry Size MB RAID Write Mode 5 WRITE BACK 1 658 6 WRITE BACK Figure 4 4 Selecting the Write Policy Option Manual No 771953 4 3 Administering the Array 3 The cursor will move to the system drive definition table 4 Position the cursor on the system drive of interest and press the Enter key to change the write policy for the selected drive 5 Repeat step 4 above to select and change the write policy for other system drives 6 Press the Esc key to return to the System Drive Definition menu 7 Make other changes as described below or proceed to Saving the Updated Configuration to Memory
111. re 4 36 MYLEX Disk Array Controller Configuration Utility Version nem nn dd uy n Channel nn Target DACI66XX tn Firmware version n m Edit Uieu Parameters Hardware Paraneters Physical Parameters SCSI Xfr Parameters Startup Paraneters Choose this option to view or edit the controller s changeable SCSI transfer parameters like wide SCSI etc Enter Channel Figure 4 36 Enter the Channel Number e Type the channel number and press Enter or simply press Enter to accept the default The SCSI Transfer Parameters menu appears specifying the appropriate Manual No 771953 4 35 Administering the Array channel Figure 4 37 MYLEX Disk Array Controller Configuration Utility Version n nn nn dd uy n Channel nn Target DACI6BXX iin Firmware version n m SCSI Transfer Parameters of Channel 1 Data transfer rate MHz 26 MHz Command tagging Enabled SCSI data bus vidth 16 Bit Figure 4 37 SCSI Transfer Parameters Menu To change a SCSI transfer parameter do the following 1 Highlight the desired parameter using the cursor keys 2 Press the Enter key to change the value 3 When the correct value is displayed either Repeat steps 1 amp 2 above but for a different parameter or Press the ESC key to return to the Edit View Parameters menu The change will be retained Data Transfer Rate MHz The SCSI T
112. re below 1 Select New Configuration from the Main menu Figure 3 19 MYLEX Disk Array Controller Configuration Utility Version n nn nn dd uy n Channel nn Target DACIGBXX iin Firmware version n m Hain Menu Bi B2 63 Ba B3 B6 a7 BB aa 1B Automatic Configuration New Configuration View Update Configuration Rebuild Initialize System Drive Consistency Check Tools Select DAC96H fiduanced Functions Diagnostics Choose this option to do a fresh custom configuration Configuring the adapter involves creating packts arranging the created pack s followed by creating System drive s Figure 3 19 New Configuration Option 3 20 DACCF Utilities Preparing the Array MYLEX Disk Array Controller Configuration Utility Version nem nn dd uy n Channel nn Target DACI66XX tn Firmware version n m Neu Configuration 1 Define Pack Z Define System Drive Choose this option to create arrange cancel one or more packs and also to vieu information on the physical drives connected to the adapter Figure 3 20 New Configuration Define Pack 2 Select Define Pack from the New Configuration menu Figure 3 20 This option is used to define drive groups also called packs The Pack Definition menu will be displayed Figure 3 21 MYLEX Disk Array Controller Configuration Utility
113. rmance than is possible with individual drives No redundancy is provided 1 Drives are paired and mirrored All data is 100 duplicated on an equivalent drive 5 Data is striped across several physical drives Parity protection is used for data redundancy 0 1 Combination of RAID levels 0 and 1 Data is striped across several physical drives This level provides redundancy through mirroring Mylex RAID 6 JBOD Just a Bunch of Drives Each drive is operated independently like a normal disk controller or multiple drives may be spanned and seen as a single large drive This level does not provide data redundancy Mylex RAID 7 Striped 0 1 Also known as 0 1 0 and 5 0 these two variants combine Striped 5 striping either with RAID level 0 1 or with RAID level 5 Manual No 771953 2 3 Configuration Strategies RAID 1 Mirroring The controller duplicates data from one drive to another Benefits Provides 10046 data redundancy Should one drive fail the con troller simply switches reads and writes to the other drive Drawbacks Requires two drives for the storage space of one drive While a controller is rebuilding a drive users will experience reduced performance if they try to read or write data Uses When array availability is most important Drives Minimum 2 Maximum 2 RAID 5 Striping with Parity The controller stripes blocks of data and parity information across all drives Benefits Uses a
114. ror count for any device should be zero Miscellaneous errors All other errors e A device times out on a command issued to it by the DAC960 The cur rent time out limit for a read write command to a disk is six seconds e An active device was busy when the controller attempted to send it a command Manual No 771953 4 43 Administering the Array 4 44 DACCF Utilities Appendix A DACCF File List DAC960 Series controllers are shipped with a number of software support files on a distribution diskette that is formatted for use with MS DOS The tables below display the structure and content of the distribution disk for the DAC960 product families Host Based DAC960 Products Directory Filename DACCFG DACCF EXE DOS ADPIDAC SYS DACDRVR SYS DAFCDA EXE UTILS DAC960FL EXE SCSI TO SCSI DAC960 Products Directory Filename DACCFG DACCF EXE READCFG ME FIRMWARE FW EXE TOOLS SLP1TK EXE TERM7 EXE DISKLIST EXE READDAC ME Manual No 771953 A 2 DACCF Utilties Appendix B Frequently Asked Questions How do set up a standby drive using DACCF When initially creating the drive groups do not include one or more drives in a drive group The drive should have a status of RDY After drive groups have been arranged and the configuration saved the excluded drives assume a status of SBY or Standby There s another way to create standby drives and that s detailed b
115. rrect the integrity of a particular redundant system drive do the following 1 Select Consistency Check from the Main menu Figure 4 12 MYLEX Disk Array Controller Configuration Utility Version n nn nn dd uy n Channel nn Target DACI66XX tn Firmware version n m Main Menu H1 Automatic Configuration BZ Heu Configuration H3 View Update Configuration B4 Rebuild BS Initialize Sustem Drive 47 Tools BB Select D CIG6A 49 Advanced Functions 18 Diagnostics Choose this option to verify the consistency of a redundant System drive Consistency may be restored if the System drive is found to he inconsistent Figure 4 12 Consistency Check Option 2 Choose Select System Drive from the Consistency Check menu Figure 4 13 4 12 DACCF Utilities Administering the Array MYLEX Disk Array Controller Configuration Utility Version nem nn dd uy n Channel nn Target DACI66XX tn Firmware version n m Consistencu Check 1 Select Susten Drive Z Start Check Choose this option to select System driue to he checked for consistencu Figure 4 13 Consistency Check Menu The Consistency Check screen will appear Figure 4 14 MYLEX Disk Array Controller Configuration Utility Version nem mmddyy n Channel nn Target DACIGBXX tn Firmware version n m Consistency Check Dex tj 4 Sus Dru
116. rrors Select the View Rebuild BBT option to determine which drive has errors Manual No 771953 4 41 Administering the Array View Write Back BBT During normal operation if you have a system drive s write policy set to write back a second bad block table is maintained in the controller s memory This table is updated whenever an error occurs during a read or write operation Error Counts for a Device The Mylex DAC960 Series controllers maintain several tables of disk errors that are encountered during normal operation These tables are called error count tables To view the error counts for a device do the following 1 Select Error Counts from the Tools menu 2 The highlighted cursor will be positioned at the first device on the chan nel of the lowest numeric value 3 Using cursor keys or a pointing device select any disk device that is displayed 4 The Error Counts Table for that device will be displayed Figure 4 42 MYLEX Disk Array Controller Configuration Utility Version n nn nn dd uy n Channel nn Target DACI66XX tn Firmware version n m Tgt Channel Number ID B 1 Tools aL so 1 Bad Block Table oh a p ta CS Lr 7 Clear Configuration aL IE 1 B Print Configuration sel C Target ID id 3 r3 v aS OE Hard Errors Misc Errors Figure 4 42 Error Counts for a Device Error Count Tables can be used to monitor the health of a device and to ind
117. rsion n m Pak Drus Size MB System Drive Definition n 3 3439 1 Create System Drive 2 Toggle Write Policy Sys Dry Size MB RAID Write Mode Figure 3 28 System Drive Definition Menu 3 28 DACCF Utilities Preparing the Array 2 Note that the size as specified in the arranged pack table will be the sum of the formatted capacity of the drives in the pack see note below The size as specified in the system drive table will be the actual size of the system drive taking into consideration the RAID level and redun dancy overhead The size of the system drive is what the various operat ing systems will see and be able to use Note If the drives in a drive group are of different capaci ties then the size of the entire pack is the product of the number of drives in the pack and the size of the smallest drive in the pack 3 Select Create System Drive from the System Drive Definition menu The first arranged pack is selected MYLEX Disk Array Controller Configuration Utility Version n nn nndd yy n Channel nn Target DACI6BXX tn Firmware version n m Pak4 Drvus Size MB System Drive Definition AY 3 3039 1 Create System Drive Z Toggle Write Policy Sus Dru Size MB RAID Write Mode RAID Level Figure 3 29 Selecting the RAID Level 4 The
118. s controller at a time If you have a single DAC960 Series controller in your system DACCF will auto matically detect and select it You can ignore this section and proceed to Set Controller Parameters for Your Application on page 3 8 If more than one DAC960 is detected in your system DACCF will ask you which controller to perform operations upon Figure 3 5 Select DAC DAC360P PCI DAC9608 at T Figure 3 5 Select which DAC960 to operate upon Select the desired controller and after a brief interrogation of the devices attached to that controller the Main menu Figure 3 4 will appear To select a different DAC960 to perform operations upon 1 Choose Select DAC960 from the Main menu 2 A list of controllers will appear The currently selected controller will be highlighted 3 Move the cursor to a different controller and press the Enter key to select that controller After a brief pause while the system interrogates the array the Main menu will display Manual No 771953 3 7 Preparing the Array Set Controller Parameters for Your Application Each DAC960 Series controller is shipped from the factory with default set tings which have been found to work well in a majority of applications and environments However no two environments are the same and you may want to modify certain hardware settings before continuing with the prepara tion of your array The most important parameters are explained below Con
119. spanned and seen as a single drive This level does not provide data redundancy Mylex RAID 7 Note The host operating system drivers and software utili ties remain unchanged regardless of the level of RAID installed The controller makes the physical configura tion and RAID level implementation transparent to the host operating system Replacement Table A replacement table contains information regarding which SCSI devices have been replaced by others through standby replacement Rotated XOR Redundancy This term also known as parity refers to a method of providing complete data redundancy while requiring only a fraction of the storage capacity of mirroring In a system configured under RAID 5 which requires at least three SCSI drives all data and parity blocks are divided between the drives in such a way that if any single drive is removed or fails the data on it can be reconstructed using the data on the remaining drives XOR refers to the Boolean Exclusive OR operator In any RAID 5 array the capacity allo cated to redundancy is the equivalent of one drive Manual No 771953 G 5 Glossary SCSI Drive A disk drive equipped with a SCSI interface sometimes referred to as a SCSI Disk Each disk drive will be assigned a SCSI address or SCSI ID which is a number from 0 to 7 0 to 15 under Wide or Ultra SCSI The SCSI address uniquely identifies the drive on the SCSI bus or channel SCSI Drive States
120. ssage 3 16 DACCF Utilities Preparing the Array 3 If no errors are encountered but a valid array configuration already exists DACCF will warn you that you are about to replace the configu ration with the structure created by the Automatic Configuration A con firmation Figure 3 15 is required to proceed MYLEX Disk Array Controller Configuration Utility Version nem nn dd uy n Channel nn Target DACI66XX tn Firmware version n m Automatic Configuration tt WARNING ff A valid configuration exists Proceeding further will destroy this configuration Do you want to proceed with Configuration D I YES Figure 3 15 Confirming Automatic Configuration Select YES to proceed overwriting the existing configuration with the automatically generated configuration Select NO in the confirmation box to return to the Main menu with no changes to the array configuration 4 Next select whether you wish to reserve one available unconfigured drive to be used as a hot spare standby drive Figure 3 16 Manual No 771953 3 17 Preparing the Array MYLEX Disk Array Controller Configuration Utility Version n nmn nn dd uy n Channel nn Target DACIGBXX tn Firmware version n m Automatic Configuration Do you wish to have a Hot Spare YES Figure 3 16 Deciding Whether to Reserve a Hot Spare Select YES to s
121. t Channel Number ID A 1 Tools aL Ced 1 Bad Block Table Y Gi es A GA 5 Mill Drive IU Gv 4 EA Ll 8 Print Configuration A Backup Restore Conf ET EE Restore Configuration Figure 4 21 Backup Restore Conf Menu Manual No 771953 4 19 Administering the Array Backup Configuration 1 4 20 Select the Backup Configuration option to back up the current DAC960 configuration to a file on a disk You ll be prompted to specify the name and location of the backup file Figure 4 22 The filename can be up to 10 characters including the drive prefix Avoid using full path names Mylex suggests that you name the file so that you can easily rec ognize it when you need it for example RAID CNF or ARRAY CNF MYLEX Disk Array Controller Configuration Utility Version n nn nndd yy n Channel nn Target DACIGBXX iin Firmware version n m Tgt Channel Number ID A 1 Tools NL aL p a 1 Bad Block Table NL 2 Error Counts 123 Cid 3 Format Drive BY NL 4 Make Online 20 5 5 Kill Drive NL 6 Backup Restore conf 3 EA Ba Y Clear Configuration NE Ll 8 Print Configuration 4 NL Anar ET Enter File Name NL ela CA gt PAS L Figure 4 22 Specify a File Name for Backup of the Configuration DACCF Utilities Administering the Array 2 Enter the name of the file and press the Enter
122. this function 4 30 DACCF Utilities Administering the Array Automatic Rebuild Management The Array Encl Mgmt I F AEMD option refers to the Automatic Rebuild Management function which works in conjunction with features in AEMI Array Enclosure Management Interface certified disk array enclosures It detects the removal of a failed drive and performs an automatic rebuild after a replacement drive is installed into a redundant fault tolerant logical array RAID 1 RAID 5 and RAID 1 0 Automatic Rebuild Management requires hardware compatibility with disk array enclosures that are certified AEMI compliant Operational Fault Management The Storage Works Fault Mgmt TM option monitors and reports drive fail ures background activity completion status enclosure events etc This function should remain enabled during normal controller operation Do not disable this function unless specifically instructed to do so as part of a trouble shooting diagnostic activity Physical Parameters Physical parameters define the interaction between the controller and the disk drives To change any physical parameter select Physical Parameters from the Edit View Parameters menu Figure 4 33 MYLEX Disk Array Controller Configuration Utility Version n nn nn dd uy n Channel nn Target DACI66XX tn Firmware version n m Edit Uieu Parameters Hardware Paraneters Physical Parameters SCSI Xfr Paraneters St
123. tion is taking place reducing the performance of the array The rebuild operation takes the array from a critical condition to a normal condition Not fault tolerant No fault tolerant RAID levels have been configured for any of the drives in the array An additional measure of fault tolerance or improved availability can be achieved using a hot spare or standby disk This disk is powered on but idle during normal array operation If a failure occurs on a disk in a fault tolerant set the hot spare disk takes over for the failed drive and the array continues to function in a fully fault tolerant mode after it completes its automatic rebuild cycle This means that the array can suffer a second drive failure and continue to function before any disks are replaced Impact of Controller Cache on Availability Every DAC960 Series controller has a disk cache This DRAM or EDRAM physical memory is used to increase the performance of data retrieval and storage operations The amount of disk cache varies with the controller model but is usually on the order of 4MB of cache RAM The controller will use this memory to store disk writes 2 12 DACCF Utilities Configuration Strategies The controller may report to the operating system that the write is complete as soon as the controller receives the data This is referred to as Write Back WB cache This will improve performance but will expose you to data loss if a system crash or power fa
124. troller parameters are set via the Advanced Functions option from the Main menu See the section on Advanced Functions in Chapter 4 Stripe Size The stripe size is defined as the size in kilobytes 1024 bytes of a single I O operation A stripe of data data residing in actual physical disk sectors which are logically ordered first to last is divided over all disks in the drive group Available stripe sizes are 8K 16K 32K and 64K For firmware versions below 2 6 the default stripe size for Mylex DAC960 Series controllers is 8K For firmware versions at or above 2 6 the default stripe size is 64K Once set the stripe size cannot be changed without first copying all of the data off of the array changing the stripe size reinitializing the drives and copying the saved data back onto the array In a large capacity array this operation could take hours and inconvenience many people You should evaluate your needs now and make any changes necessary before the array is placed in service 3 8 DACCF Utilities Preparing the Array Segment Size DAC960 firmware version 2 6 and above includes an additional user config urable parameter segment size Segment size is set in conjunction with stripe size and represents the size of the data chunk that will be read or written at one time Under DACCF the segment size also known as cache line size should be based on the stripe size you selected Refer to Table 3 1 below for the avail
125. troller to read into cache a full stripe of data at a time This greatly improves the percentage of cache hits 4 32 DACCF Utilities Administering the Array For example if the stripe size is set to 8k and the host requests 1k of data when this function is enabled the controller will read ahead the full 8k When the host requests the next 1k block that data will already be in the controller s cache Note Users of DAC960 firmware version 2 6 and above may disable this option The controller adaptively reads ahead in any case Firmware below version 2 6 does not possess adaptive read ahead caching so this function should remain enabled during normal con troller operation Super Read Ahead DAC960S Only The Super Read Ahead function for DAC960S controllers increases perfor mance for applications that must access large blocks of sequential data This function incorporates intelligent data request monitoring to track data requests by the host With Super Read Ahead enabled the controller detects requests for data that are stored in sequence on the drives It reads the data into the cache so that the cache remains at least one request ahead of the host This function if available should remain enabled during normal controller operation Segment Size The Segment Size function available in DAC960 firmware version 2 6 and above is set in conjunction with stripe size and represents the size of the data chunk that will be read
126. uration One of the primary functions of DACCF is to create logical storage units also known as logical disk drives from an array of physical disk drives A defined size or capacity and a particular RAID level is associated with each logical drive Once defined and initialized these logical drives are presented by the DAC960 Series controller to the operating system Note Run DACCF to configure and initialize the array before installing the operating system programs or data onto the disk array While DACCF allows for unlimited customization in the configuration of logical drive sizes and RAID levels associated with these drives an auto matic configuration option is available as well When invoked this option will optimize the amount of available capacity performance and fault toler ance for a given number of physical disks If you re new to the concept of RAID we recommend that you select automatic configuration for a first time installation Initialization After an array has been configured it must be initialized The initialization process is similar to but not the same as formatting of a disk Array initial ization is performed from within DACCF Managing the Array After the array has been configured initialized and loaded with information DACCF is used to manage the array particularly when an environmental system or hardware malfunction occurs that could put data stored in the array at risk DACCF provides the
127. uration and the unconfigured drive s as standby drives 15 Verify that the drive is a standby drive by selecting View Update Con figuration again from the Main menu The replacement drive should have a status of SB Y Pve replaced a drive that the controller made dead Now what do I do to recover the data The following procedure will only work for replaced drives that are part of a RAID 1 5 or 6 drive group Using the Main menu do the following 1 Select Rebuild 2 Highlight the drive that has been replaced The status should read DED Press the Enter key 3 DACCF will ask you if you want to low level format the drive e fthis is a new drive that has not been used in this array before allow the drive to be low level formatted before the rebuild takes place by answering YES Answering NO will skip the low level format and proceed directly to the rebuild of data on the new drive 4 Any defined system drives will then be rebuilt on the new drive in sequential order How do I change the write policy on a existing configuration To change the write policy follow these steps 1 Select View Update Configuration from the Main menu 2 Select Define System Drives from the View Update Configuration menu Manual No 771953 B 3 Frequently Asked Questions 3 Select Toggle Write Policy from the System Drive Definition menu 4 Highlight the desired system drive using a mouse or the cursor ke
128. ve status present or absent and the write policy write back or write through caching is selected during the configura tion process e The system drive number is 0 Automatic Configuration Procedure 1 Select Automatic Configuration from the Main menu Figure 3 13 Manual No 771953 3 15 Preparing the Array MYLEX Disk Array Controller Configuration Utility Version nem nn dd uy n Channel nn Target DACI66XX tn Firmware version n m Main Menu BZ New Configuration B3 View Update Configuration B4 Rebuild H5 Initialize System Drive 46 Consistency Check B7 Tools BB Select DACI64 49 Advanced Functions 18 Diagnostics If 3 or more Physical drives are present choose this option to create one RAID 5 System drive automatically Figure 3 13 Automatic Configuration Option 2 An error message will be displayed if fewer than 3 or more than 8 drives are detected or if drives of differing capacities are found The Auto matic Configuration will then abort and an error message will appear Figure 3 14 MYLEX Disk Array Controller Configuration Utility Version nem nm dd yy n Channel nn Target DACI6HXX tn Firmware version n m Automatic Configuration Automatic configuration FAILED as all drives are not of the same size OR the number of drives is less than 3 or greater than 8 Figure 3 14 Automatic Configuration Failure Me
129. x recommends that you make a backup copy of the con figuration to diskette and store the diskette in a safe place If necessary a new array can be completely configured by restoring the backup configura tion from the diskette Note Any errors encountered in reads or writes to the disk during a backup restore or print configuration process will result in the message Retry or abort Choosing abort will exit DACCF 1 Recommended if using DAC960 firmware versions below 3 0 Firmware version 3 x employs configuration on disk and does not require manual backup and restore Manual No 771953 4 17 Administering the Array Backup Restore Configuration Note USERS OF DAC960 FIRMWARE VERSION 3 0 AND ABOVE may skip this section The configuration on disk feature of firmware version 3 0 and above automatically saves the current configuration to the disk drives without user intervention Should a con troller fail the saved configuration is restored to the new controller from the information contained on the drives In most cases manual backup restore should not be used USERS OF DAC960 FIRMWARE VERSION 2 6 OR BELOW must perform manual backup and restore as described below To backup or restore a configuration do the following 1 Select Tools from the Main menu Figure 4 19 MYLEX Disk Array Controller Configuration Utility Version n nmn nn dd uy n Channel nn Target DACIGBXX iin Firmware version n
130. y PgDn and PgUp to view additional devices on the channels MYLEX Disk Array Controller Configuration Utility Version n nn nndd yy n Channel nn Target DACI66XX tn Firmware version n m Main Menu BZ Heu Configuration H3 View Update Configuration B4 Rebuild BS Initialize System Drive 46 Consistency Check B7 Tools BB Select DACI64 49 Advanced Functions 18 Diagnostics If 3 or more Physical drives are present choose this option to create one RAID 5 System drive automatically Figure 3 2 DACCF Selecting an ltem Once highlighted via either of the above methods an item is selected by pressing the Enter key Exiting a Menu Use the Escape key the key labeled ESC to return to the previous action or state For example if you select the wrong menu choice press the Esc key and you will return to the original menu Using a Mouse A mouse or other pointing device can also be used to navigate the DACCF menus You ll need to have loaded a mouse driver prior to running DACCF To position the highlight bar on a menu item position the mouse cursor as opposed to the highlighted bar on the item and single click the left mouse button To select an item position the mouse cursor on a highlighted item and single click the left mouse button 3 4 DACCF Utilities Preparing the Array Starting DACCF To start DACCF type A DACCF at the MS DOS command prompt an
131. ys and press the Enter key to change the write policy for that drive 5 Repeat step 4 for other system drives 6 When finished press the ESC key twice and answer YES when prompted to save the configuration Do I need to initialize the system drive again after changing the con troller cache write policy No Initialization of the system drive will erase any data that is stored on it When I make a new drive on line all my data is corrupted When should use the Make On line option The Make On line option should only be used in an emergency situation when data has to be recovered from a disk array It can be used if a fault tol erant array is running in a critical state that is a drive has failed and the array is reading and writing using mirror or parity information and another drive failure occurs At this point the array has lost the ability to store data The Make On line option forces the drive on line so that the information can be copied to another medium Use the Rebuild function to reconstruct data on a new drive that has just replaced a failed drive Why do I need to copy DACCF to a boot disk I don t even have a sec ond floppy drive Putting DACCF on a bootable floppy disk is suggested merely as a conve nience It s not an absolute requirement Having a boot disk with DACCF just makes life easier when installing the array for the first time or in the event that a situation occurs where the array c

DACCF Utilities Installation Guide and User Manual

Contents

Download Pdf Manuals

Related Search

Related Contents