SnapSAN S5000 AutoCache User Guide
Contents
1. It is necessary to disable the L2 cache function beforehand and unbind the L2 cache when the process is complete Attn reconstructing is displayed for the L2 cache status while the process to disable the L2 cache function is running Set names e Pool name Specify a name for the L2 cache pool Logical disk name 1 Logical disk name 2 Logical disk name 3 Specify a name for up to three special logical disks corresponding to the L2 cache e Specify a name for the L2 cache pool according to the rules below The characters violating these rules cannot be specified e Number of usable characters 1 to 32 characters e Usable characters Alphabets A to Z a to z The name is case sensitive Number 0 to 9 Underscore _ Slash e All characters must be one byte e Specify a name for the logical disk for L2 cache according to the rules below The characters violating these rules cannot be specified e Number of usable characters1 to 24 characters 10400410 002 11 2012 2012 Overland Storage Inc lt q 2 11 SnapSAN S5000 AutoCache User Guide L2 Cache Settings e Usable charactersAlphabets A to Z a to z The name is case sensitive Number 0 to 9 Underscore _ Slash e All characters must be one byte e An existing pool name must not be specified for the L2 cache pool e Itis not allowed to assign the same name to the two logical disks for L2 cache An existing logical disk name must not be assigned ei2. L2 Cache Purpose of L2 Cache This chapter describes the L2 cache basics L2 cache is a cache placed on an SSD which has high random access performance By introducing an L2 cache into a disk array response when random access concentrates in the storage can be improved Application server Logical disks Figure 1 1 L2 Cache An L2 cache of the storage is used as a read cache write cache or persistent write described below e Read Cache Data that is frequently read by random access is stored in an L2 cache If the data does not exist in the L1 cache 1 when a read request for this data is made again this data is read from the L2 cache that is faster to access than HDD Hard Disk Drive The L2 cache of this type is effective for operations involving a lot more data reads than writes such as those with indexes of a database or a boot drive in a virtual desktop environment e Write cache When a lot of write requests are issued the response to a write request is improved by moving unwritten data existing in cache to the L2 cache instead of writing itin HDD e Persistent write When a controller is degraded due to a failure the cache usually enters write through 2 state to maintain the data integrity and the response to a write request will be decreased By using the L2 cache function the cache of the failed controller is substituted by the L2 cache This prevents the response to a write request from being decreased if a fa
3. License For a copy of the license see http arcib dowling edu cgi bin info2htm1 flex info gz Copyright 10400410 002 11 2012 2012 Overland Storage Inc lt A 1 overland lt j storage Index A advanced settings for L2 cache bind 2 6 AutoCache 3 1 C Cache module list 2 14 Change of L2 cache settings 2 1 Checking for the Read Cache Usage 4 9 Checking for the Write Cache Usage 4 10 Confirming Effects of Read Cache Installation 4 2 conventions typographical PR iv customer support PR iii E expanding the L2 cache capacity 4 11 H Handling When L2 Cache Is Degraded 4 12 I isMcfg l2cachebind 2 2 isMcfg l2cacheunbind 2 2 iSMcfg nickname 2 2 isMcfg setl2cacheattr 2 2 L L1 L2 cache hit ratio 2 14 4 3 L2 Cache 4 1 L2 cache average dirty pages 4 8 L2 cache bind 4 1 L2 cache configuration 1 2 L2 cache information display 2 1 L2 cache maximum dirty pages 2 15 10400410 002 11 2012 L2 Cache On Off for Each Logical Disk 2 12 L2 cache on off for each logical disk 2 2 L2 cache page in size 2 14 L2 Cache Performance Analysis 2 2 L2 cache performance analysis 2 1 L2 Cache pool 2 6 L2 Cache Settings 2 2 L2 Cache Type 2 5 L2 Cache Types 1 2 logical disk for L2 Cache 2 7 N name for the L2 cache pool 2 7 name for the logical disk for L2 cache 2 7 O Overland Technical Support PR ili P Persistent write 1 1 persistent write 1 1 physical disk 2 3 Physical disk list 2
4. Settings e Itis not allowed to assign the same name to the two logical disks for L2 cache An existing logical disk name must not be assigned either e Ifyou click the OK button with nothing entered in the Pool name field and or Name of the logical disks for L2 Cache field names are assigned automatically Completion The result of the L2 cache bind is displayed LZ Cache Bind Binding L2 Cache succeeded Click Finish to exit Monitoring of the disk array resumes Back Figure 2 7 L2 Cache Bind Completion Navigation button s e Finish The Monitor Screen Display screen is displayed If the L2 cache bind fails check the physical disk list on the Monitor Screen Display screen and see if there are physical disks allocated to L2 cache Also check the disk array for abnormalities If physical disks remain allocated to L2 cache after troubleshooting of the disk array perform L2 caches unbind once L2 Caches Unbind Release the L2 cache The L2 Cache Unbind screen consists of the following screens e L2 Cache Unbind e Completion L2 Cache Unbind The L2 cache settings to be released are displayed 10400410 002 11 2012 2012 Overland Storage Inc lt 2 8 SnapSAN S5000 AutoCache User Guide L2 Cache Settings Lz Cache Unbind LZ Cache Unbind gt Completion L2 Cache Information Name of the L2 Cache pool Pool0004 L2CHE L2 Cache Type z Read Write Physical disks to be
5. analysis by the hourly summary Figure 4 11 AutoTune Graph Showing L1 Cache Hit Ratio Change analysis items 10400410 002 11 2012 2012 Overland Storage Inc lt 4 7 SnapSAN 5000 AutoCache User Guide Initial Configuration In Configure Settings change the metric to be displayed to the L2 cache average dirty pages Ei Read Read Hit Prefetch Read Hit I O Type i Total E Write Ei Bead Total Hit Wrice Hit Read Hit Prefetch Read Hit Note Select the Statistic Information type I O type Cap type and value for analyze Display in new window Figure 4 12 Auto Tune Configure Settings Execute advanced analysis If the ratio of the L2 cache average dirty pages is larger than 0 the write cache of the L2 cache has been used Efficient use of the write cache of the L2 cache improves the response to write requests when the L1 cache hit ratio Write is less than 100 Figure 4 13 AutoTune Graph Showing L1 Cache Avg Dirty Pages 10400410 002 11 2012 2012 Overland Storage Inc 44 8 SnapSAN S5000 AutoCache User Guide Initial Configuration Checking for the Read Cache Usage This section describes the procedure for checking for the usage of the read cache of the L2 cache by using AutoTune after installing the read cache of the L2 cache It is assumed that the license for Performance Monitor is unlocked and accumulation of metrics of the disk array is started already Step 1 Im
6. are familiar with computer hardware data storage and network administration terminology and tasks It also assumes you have basic knowledge of Internet SCSI GSCSJ Serial attached SCSI SAS Serial ATA SATA Storage Area Network SAN and Redundant Array of Independent Disks RAID technology Product Documentation and Firmware Updates Overland Storage SnapSAN product documentation and additional literature are available online along with the latest release of the SnapSAN 5000 AutoCache User Guide software Point your browser to http docs overlandstorage com snapsan Follow the appropriate link to download the latest software file or document For additional assistance search at http support overlandstorage com Overland Technical Support For help configuring and using your SnapSAN S5000 search for help at http support overlandstorage com kb You can email our technical support staff at techsupport overlandstorage com or get additional technical support information on the Contact Us web page http www overlandstorage com company contact us For a complete list of support times depending on the type of coverage visit our web site at http support overlandstorage com support overland_care html 10400410 002 11 2012 2012 Overland Storage Inc lt iii 10400410 002 11 2012 Convention Boldface Ctrl Alt r NOTE IMPORTANT CAUTION A WARNING A Menu Flow Indicator gt
7. component Replace the faulty physical disk When the process to restore the L2 cache starts a message SnapSAN Manager07643 indicating the L2 cache is during restoration processing is displayed 3 Check the L2 cache state On the completion of restoring the L2 cache a message SnapSAN Manager07640 indicating the L2 cache was restored is displayed 10400410 002 11 2012 2012 Overland Storage Inc lt 4 4 13 overland storage Appendix A Notes Notes for L2 Cache General notes for using the L2 cache function are described below Licenses The data on the logical disks in a normal pool that is configured on SSD disks are not stored in the L2 cache If the read cache on a logical disk is set to disabled the L2 cache on that logical disk is also disabled One L2 cache can be created per disk array The rated number of physical disks that can be set for L2 cache is four But in the case of the read only it is two In the L2 cache pool three logical disks for the L2 cache are bound A normal logical disk cannot be created in the pool dedicated to L2 cache Operations that are not related to L2 cache cannot be performed on the logical disks dedicated to L2 cache L2 cache cannot be created on the physical disk in which the disk array configuration information is saved Apache License For terms and conditions for use reproduction and distribution see http www apache org licenses LICENSE 2 0 Flex
8. of L2 Cache Performance Analysis o cccceccscsccssssescessssssscscssssssscsessessssescssesesesesesescecseesseeees 2 14 Chapter 3 L2 Cache Function Installation S Eaa o e Ea E AEE EAA A A N E A A E E EEE AAE E E E 3 1 SCC OCG Le a E 3 1 SOV le ASTONGINOTY eea E Costar eita E AE AR E E E 3 2 Chapter 4 L2 Cache Operation EO O arase a E EEE E EEE EAEE 4 Confirming Effects of Read Cache Installation e ssesesesssssesseesseessrresseessressresseessreessressereseeesseesseesssseeeseees 4 2 Confirming Effects of Write Cache Installation sessssesseessesessesssesssessseesseeeserssneessresssesssresseesseessneesesseeessee 4 6 Checking for the Read Cache USAGE cccsescccsssssccessscscssscscesssesecessaeesenssesssnssesscesseesecssseseveceesevesseseveneas 4 9 Checking tor th Write Cache Usgqge aerrs sare css evens alot Reaessusteedtawnsusnaeoninnsas eneitaaea n a a EA aienea ian 4 10 PCNN A S C AR I aa T N A A A 4 11 Handling When L2 Cache Is Degraded sesessessresseressrerseressresseereoresserssorssseereseesreesseessrerssoesseeseeessresssresses 4 12 Appendix A Notes OTS A T E E E E ee A UN NS cesar ree seen R O se vee cepacia ps A O E AT A A A EEA A PACING ECS Is cares ose E E A E A E T EEEE EE A E EE EE A 10400410 002 11 2012 2012 Overland Storage Inc lt 1 SnapSAN S5000 AutoCache User Guide Flex License Index 10400410 002 11 2012 2012 Overland Storage Inc lt 42 overland storage enagien
9. of the L2 cache by using AutoTune after installing the write cache of the L2 cache For how to operate AutoTune refer to the Performance Analysis User s Manual It is assumed that the license for Performance Monitor is unlocked and accumulation of metrics of the disk array is started already 10400410 002 11 2012 2012 Overland Storage Inc lt 4 10 SnapSAN 5000 AutoCache User Guide Initial Configuration Step 1 Import metrics 1 Step 2 Change the application settings Step 3 Change the quick analysis settings Step 4 Execute quick analysis Step 5 Change the analysis items 4 Step 6 Execute advanced analysis Figure 4 17 Procedure for Checking for the Write Cache Usage Figure 4 18 AutoTune Graph Showing L2 Cache Average Dirty Pages Expanding the Capacity This section describes the procedure for expanding the capacity of the L2 cache through configuration setting on the SnapSAN Manager client GUI after installing the L2 cache The L2 cache function must be stopped before expanding the L2 cache capacity Note that the I O response may be decreased by stopping the L2 cache function Therefore it is recommended to implement work in the low time zone of the load 10400410 002 11 2012 2012 Overland Storage Inc lt 4 11 SnapSAN 5000 AutoCache User Guide Initial Configuration Step 1 Start changing the L2 cache settings Step 2 Stop the L2 cache function Step 3 End changing the L2 cache sett
10. 02 11 2012 2012 Overland Storage Inc 44 5 SnapSAN S5000 AutoCache User Guide Initial Configuration Confirming Effects of Write Cache Installation This section describes the procedure for checking that the write cache of the L2 cache is used effectively by using AutoTune after installing the write cache of the L2 cache It is assumed that the license for Performance Monitor is unlocked and accumulation of metrics of the disk array is started already Step 1 Import metrics Step 2 Change the application settings Step 3 Change the quick analysis settings Step 4 Execute quick analysis Step 5 Change the analysis items Step 6 Execute advanced analysis Figure 4 9 Write Cache Installation Confirmation Change the quick analysis settings In Configure Quick Analysis set the default template for the cache hit ratio to be displayed in quick analysis 10400410 002 11 2012 2012 Overland Storage Inc 44 6 SnapSAN 5000 AutoCache User Guide Initial Configuration Restrict Timeframe Type Interval Period From 02 15 2012 09 47 to 02 16 2012 09 46 Mon Tue Wed Thu Fri Sat Sun Change Figure 4 10 AutoTune Configure Quick Analysis Execute quick analysis Execute Quick Analysis The L1 cache hit ratio graph is displayed When the L2 cache hit ratio Write is 100 all write requests have been processed by the L1 cache and the L2 cache has not been used In this example it is executing the quick
11. 14 product documentation PR iii R Read Cache 4 2 Read only 1 2 S SnapSAN Manager 2 13 software update PR iii SSD 2 4 2012 Overland Storage Inc lt 4 1 1 SnapScale RAINcloudOS 3 0 Administrator s Guide T technical support PR iii Total Capacity 2 14 typographical conventions W Write Cache 4 6 write cache 2 15 10400410 002 11 2012 PR iv 2012 Overland Storage Inc lt 4 1 2
12. 2CHE_yyyy xxxx Pool number yyyy Logical disk number It is recommended to operate the L2 cache without changing the initial nicknames in order to make it identifiable as L2 cache by the nickname If you want to change the initial nicknames assign nicknames by which the L2 cache can be identified L2 cache configuration can be performed through the configuration setting on the SnapSAN Manager client GUI or using SnapSAN Manager ControlCommand However the L2 cache on off setting for each logical disk can be performed only through the configuration setting on the SnapSAN Manager client GUI The following table shows the menus and commands used for L2 cache configuration 10400410 002 11 2012 2012 Overland Storage Inc lt q 2 1 SnapSAN 5000 AutoCache User Guide L2 Cache Settings Configuration Setting on SnapSAN SnapSAN Manager Function Manager client GUI ControlCommand L2 cache bind Configuration L2 Cache L2 Cache SnapSAN Managercfg Bind I2cachebind L2 cache unbind Configuration L2 Cache L2 Cache SnapSAN Managercfg Unbind I2cacheunbind Change of L2 cache Configuration L2 Cache Change of L2 SnapSAN Managercfg settings Change a Cache Settings nickname nickname Change of L2 cache Configuration L2 Cache Change of L2 SnapSAN Managercfg settings Stop and Cache Settings setl2cacheattr restart the L2 cache L2 cache on off for Configuration Logical Disk Logical Not supporte
13. L2 cache settings refer to Configuration Setting Tool User s Manual GUI for the M Series L2 Cache Enables or disables the L2 cache function for the selected logical disk Disabling the L2 cache including the logical disk that is being used less than before decreases the performance of the specified logical disk On the other hand the performance of other logical disks 1s enhanced The L2 cache settings of the logical disk that meets any of the following causes cannot be changed Cause Description SYV The logical disk is a System Volume RSV The logical disk is a replication reserved volume Snapshot The logical disk is a base volume BV Snapshot volume SV or Snapshot data volume SDV LV The logical disk is a link volume LV MSV The logical disk is a data migration reserved volume SSD The logical disk is the one bound in SSD including logical disks for L2 cache Navigation button s e Set The following confirmation dialog box is displayed a Ia it OF to start Logical Disk Change Of Settings ves Figure 2 14 Confirmation Dialog Box Clicking Yes starts changing the logical disk settings e Cancel A dialog box is displayed that asks if you want to end the wizard Clicking the OK button displays the Monitor Screen Display screen without changing the logical disk settings Operations of L2 Cache Information Display This section describes operations for displaying the information ab
14. Overland S napSAN 5000 AutoCache Storage November 2012 overland 10400410 002 storage SnapSAN 5000 AutoCache User Guide 2012 Overland Storage Inc All rights reserved Overland Overland Data Overland Storage ARCvault DynamicRAID LibraryPro LoaderXpress Multi SitePAC NEO NEO Series PowerLoader Protection OS REO REO 4000 REO Series Snap Appliance Snap Care EU only SnapServer StorAssure Ultamus VR2 and XchangeNOW are registered trademarks of Overland Storage Inc GuardianOS RAINcloud SnapDisk SnapEDR Snap Enterprise Data Replicator SnapExpansion SnapSAN SnapScale SnapServer DX Series SnapServer Manager SnapWrite and SnapServer Manager are trademarks of Overland Storage Inc All other brand names or trademarks are the property of their respective owners The names of companies and individuals used in examples are fictitious and intended to illustrate the use of the software Any resemblance to actual companies or individuals whether past or present is coincidental PROPRIETARY NOTICE All information contained in or disclosed by this document is considered proprietary by Overland Storage By accepting this material the recipient agrees that this material and the information contained therein are held in confidence and in trust and will not be used reproduced in whole or in part nor its contents revealed to othe
15. SnapSAN 5000 AutoCache User Guide Conventions This user guide exercises several typographical conventions Description amp Usage Words in a boldface font Example indicate items to select such as menu items or command buttons This type of format details the keys you press simultaneously In this example hold down the Ctrl and Alt keys and press the r key A Note indicates neutral or positive information that emphasizes or supplements important points of the main text A note supplies information that may apply only in special cases for example memory limitations or details that apply to specific program versions An Important note is a type of note that provides information essential to the completion of a task or that can impact the product and its function A Caution contains information that the user needs to know to avoid damaging or permanently deleting data or causing physical damage to the hardware or system A Warning contains information concerning personal safety Failure to follow directions in the warning could result in bodily harm or death Words in bold font with a greater than sign between them indicate the flow of actions to accomplish a task For example Setup gt Passwords gt User indicates that you should press the Setup button then the Passwords button and finally the User button to accomplish a task Information contained in this guide has been reviewed for accuracy but not for product warr
16. Specify a name for the L2 cache pool First number assigned to a logical disk for L2 Cache Specify the number of the first logical disk The next available numbers following the specified number are used for the subsequent logical disks Name of the logical disks for L2 Cache Specify a character string common to names of up to three special logical disks corresponding to the L2 cache The specified name is used as the prefix of each logical disk name the actual logical disk name is generated by appending a string derived from the logical disk number to the prefix for each logical disk e Specify a name for the L2 cache pool according to the rules below The characters violating these rules cannot be specified e Number of usable characters 1 to 32 characters e Usable characters Alphabets A to Z a to z The name is case sensitive Number 0 to 9 Underscore _ Slash e All characters must be one byte e Specify a name for the logical disk for L2 cache according to the rules below The characters violating these rules cannot be specified e Number of usable characters1 to 24 characters e Usable charactersAlphabets A to Z a to z The name is case sensitive Number 0 to 9 Underscore _ Slash e All characters must be one byte e An existing pool name must not be specified for the L2 cache pool 10400410 002 11 2012 2012 Overland Storage Inc lt q 2 7 SnapSAN S5000 AutoCache User Guide L2 Cache
17. among write cache pages of the L2 cache This metrics can be displayed only when using the L2 cache of Read Write 10400410 002 11 2012 2012 Overland Storage Inc lt q 2 15 overland storage Chapter 3 L2 Cache Function Installation System Configuration A configuration example of hardware and software components for using the L2 cache function is shown below Application server eT EE i m S LINAS or Windows M series disk arrays 2 ea 1 Recommended program product or I Excluding the M10SnapSan 3000 Management Management terminal server Figure 3 1 System Configuration Example Related Products To use the L2 cache function the following related program products are required AutoCache This is the product covered in this manual It provides functions that use L2 cache SnapSAN Manager and BaseProduct This product provides functions that monitor the state of the resources of the disk array and set up the disk array configuration In addition to use the L2 cache function more effectively the following program product is recommended 10400410 002 11 2012 2012 Overland Storage Inc lt 3 1 SnapSAN 5000 AutoCache User Guide System Configuration Performance Monitor Suite Set of Performance Monitor and AutoTune This product includes the analysis function AutoTune in addition to the disk array performance monitor function Analyzing the stora
18. anty because of the various environments operating systems or settings involved Information and specifications may change without notice 2012 Overland Storage Inc lt PR iv overland J storage Contents Preface Chapter 1 L2 Cache FI sO ICS aires recessed a eee A E boccdev ea duced ne EA T E A ETO 1 1 HEC A ANE teaser wre arte alse ie needa EEA O E AA E EE 2 ES CIS CONIU aara EEA 1 2 PES A EO SS r T A E TEE E E 1 3 ONE E a ETE E E E E E A E 1 3 eS UC iS OP raona OSI a A A R N 1 3 Chapter 2 L2 Cache Function Ee Aa NS Se a E A A vasa seesienetie van eoatyeneetsancu amount secmedescietnensaactoeets 2 Opalone Or L2 Cache 5 CA ag caresses cosseectoseunisenetutastasevaee a Ei R 2 2 Number of physical disks and physical disk Capacity sesseessesssesssssesssssssressssrressssseeessssreesssreressssreeessee 2 3 SS ISN FAVS SIGS sarreria iorese orras sone EErEE rE N EEEE AEE NEE EEEE 2 4 POOO a a ea E E A AEA oaneeesantes 2 7 ING COTO DUNOMIS sesnassesnntanayeconsnsaccrsosbectsiouncmusaabuetdnon ossteougiensnuk ES ED E OE R NEE 2 8 Change Oe CSS STIS saree sisasignsarssaryscoarateras ecoratinens T EEE NEN 2 10 SOIC ie Ola OTT TOE CIC LOOCK areira ENEO 2 12 Operations of L2 Cache Information Display ou eecccsseesssssssscessssscscessseseecessssssesseessusseseccseusessessenseess 2 13 SnapSAN Manager Main WiINdOW pasa saet astuvesaisionacsaeunctessssneanesnciecseveianaesck on save caiasenceattetantaretagercsananaan 2 13 Operations
19. d each logical disk Disk Operation Change Settings L2 Cache Information Display The L2 cache information display function is capable of displaying the configuration information about the L2 cache Use this function when checking the configuration or state of the L2 cache L2 Cache Performance Analysis The L2 cache performance analysis function is capable of displaying the performance information about the L2 cache Use this function when checking effects or capacity shortage of the L2 cache Operations of L2 Cache Settings This section describes how to set up an L2 cache by using configuration setting on the SnapSAN Manager client GUI For details about L2 cache configuration through SnapSAN Manager ControlCommand refer to the Command Reference You can perform the following operations in relation to L2 cache e L2 Cache Bind e L2 Cache Unbind e Change of L2 Cache settings e Set On Off L2 Cache for Each Logical Disk L2 Cache Bind Create a new L2 cache The L2 Cache Bind screen consists of the following screens L2 Cache Bind e Physical disk selection Confirmation e Advanced settings 10400410 002 11 2012 2012 Overland Storage Inc lt q 2 2 SnapSAN S5000 AutoCache User Guide L2 Cache Settings 10400410 002 11 2012 2012 Overland Storage Inc Completion L2 Cache Bind Set the L2 cache you want to bind re eo Lz Cache Bind gt Confirmation gt Completion 1 Select a L2 Cache type 2 S
20. e Set The following confirmation dialog box is displayed me Is it OR to start LZ Cache bind luisa felled Figure 2 5 Confirmation Dialog Box If you click Yes the L2 cache bind operation is executed and then the Completion screen is displayed e Back The L2 Cache Bind screen is displayed again e Cancel A dialog box is displayed that asks if you want to end the wizard Clicking the OK button in the dialog box ends the wizard and displays the Monitor Screen Display screen Advanced Settings Set the advanced settings for L2 cache bind 10400410 002 11 2012 2012 Overland Storage Inc lt 4 2 6 SnapSAN S5000 AutoCache User Guide L2 Cache Settings Le Cache Bind Configure the advanced settings Fool name Poo lO004_L2CHE Logical disks for L Cache First number assingned to a logical disk for Lf Cache Eib h Name of the logical disks for Lf Cache Poo 10004_L2CHE Explanation Pool name Specify the name of the pool for Lz Cache First number assingned to a logical disk for Le Cache Specify the first number assinged to a logical disk for the LZ Cache The next unused numbers are assinged to the rest af logical disks Name of the logical disk for Le Cache Specify the prefix of the name of logical disks for the Lz Cache This prefix appended by a string derived from the logical disk number Will be the actual name of a logical disk Figure 2 6 Advanced Settings Pool Name
21. e base of the disk array for the L2 cache e If in manual disk selection you have chosen a combination of physical disks that differ in capacity the L2 cache is created based on the disk with the smallest capacity e For this reason when you have chosen such a combination a warning dialog box appears at the click of the Next button Select Physical Disks Select the physical disks to be used The physical disk selection section can be displayed on the List tab or View tab You can switch the display by selecting the tab at the top of the section On the List tab the physical disks that cannot be used to create an L2 cache are not displayed in the list on the View tab the corresponding check boxes are grayed out le Cache Bind select physical disks for the pool The number of disks you can select for the pool 1 Unused physical disks Fhysical disks Capacity ce Type Oo0h O016h 57 6 SSD 00h O017h B7_ 6 SSD Figure 2 2 List Tab 10400410 002 11 2012 2012 Overland Storage Inc lt q 2 4 SnapSAN S5000 AutoCache User Guide L2 Cache Settings E2 Cache Bind select physical disks for the pool The number of disks you can select for the pool 1 Unused physical disks Fhysical disks E M ease E sae 6 ae aoe I WSsToOO WOd a W ATOO oOO m Figure 2 3 View Tab L2 Cache end Li Cache Bind Confirmation gt Completion Confirm the settin
22. ge performance information allows you to confirm the effects and usage of the L2 cache Software Installation Before installing the L2 cache function you need to unlock the licenses of AutoCache and the other required program products for the target disk array 10400410 002 11 2012 2012 Overland Storage Inc lt 3 2 overland J storage Chapter 4 L2 Cache Operation Initial Configuration This section describes the procedure for creating an L2 cache through configuration setting on the SnapSAN Manager client GUD in order to use the L2 cache in applications It is assumed that the licenses for AutoCache and the other required products including storage control software are unlocked already Step 1 Start L2 cache bind Step 2 Create an L cache Step 3 End L2 cache bind Step 4 Check the L2 cache state Figure 4 1 Procedure for Initial Configuration Start L2 cache bind On the main window of the SnapSAN Manager client Web GUI select a disk array in which to create an L2 cache and select Configuration L2 Cache L2 Cache Bind to st Create an L2 cache After the L2 Cache Bind wizard starts specify the following and create an L2 cache L2 cache type Read Write or Read only Physical disks SSD disks to be used to configure the L2 cache End L2 cache bind End the L2 cache bind and resume disk array monitoring Step 4 Check the L2 cache state Displays the detailed information about the di
23. gs Basic settings Lz Cache Type Read Write Advanced settings Name of the Lz Cache pool Poold0o04 L2CHE Numbers of the logical disks for Lz Cache Oftbh Of fch Oftdh Poold004 L2CHEOFFBE Poold004 LZCHEOFFC Poold004 LZCHEOFFD Names of the logical disks for Li Cache Click Advanced for modifying the settings in the field above Physical disks of the Lz Cache pool Capacit yLCHT T 87 6 55D 87 6 55D 00h O016h 00h O017h When the settings are OR click Set to start creating the Lz Cache I you want to modify any gettings click Back or Advanced Figure 2 4 L2 Cache Bind Confirmation The settings of the physical disks to be used for the L2 cache are listed Clicking the Advanced button displays the Advanced Settings screen Basic settings L2 Cache Type 10400410 002 11 2012 2012 Overland Storage Inc lt 4 2 5 SnapSAN S5000 AutoCache User Guide L2 Cache Settings Displays the configuration type of the L2 cache e Read Write e Read only Advanced settings The following items can be changed on the Advanced Settings screen Name of the L2 Cache pool Name assigned to the special pool to which the L2 cache is allocated Numbers of the logical disks for L2 Cache Number of the special logical disk corresponding to the L2 cache Up to three numbers Names of the logical disks for L2 Cache Name assigned to the special logical disk corresponding to the L2 cache Up to three names Navigation button s
24. guration Application Settings Hode wecrics Specify the Analysis mode C dJtandard Analyse typical array resources ail array resources Resources Disk Array Hode Logical Disk Director Application Settings Mode Metrica Jpecify the metrics to analyse Standard Common metrics 1 0 Density Average Transfer Length Transfer Rate Average Response Time Max Response Time Busy Ratio I O Ratio Figure 4 4 Auto Tune Application Settings Metrics Tab 3 Change the quick analysis settings In Configure Quick Analysis set the default template for the L1 L2 cache hit ratio of the cache to be displayed in quick analysis 10400410 002 11 2012 2012 Overland Storage Inc lt 4 3 SnapSAN 5000 AutoCache User Guide Initial Configuration H FE Disk Array H A Port H O EL Host Director E eu Hit Ratio Total Write Read L L Cache Hit Ratio Read o L2 Cache Page in Size t Add Remove Save a 7 Load an Edit ra Current Loading TemplateSet The Performance Analysis of the Storage Restrict Timeframe Type Interval Period From 11 21 2011 11 01 to 11 22 2011 11 00 Mon Tue Wed Thu Fri Sat Sun Shange Figure 4 5 Auto Tune Configure Quick Analysis 4 Execute quick analysis Execute Quick Analysis The L1 L2 cache hit ratio graph is displayed In this example it is executing the quick analysis by the hourly summary Figure 4 6 AutoTune Graph Sh
25. ilure occurs 1 The L1 cache means a cache that is bound to the cache module 10400410 002 11 2012 2012 Overland Storage Inc lt 4 1 1 SnapSAN 5000 AutoCache User Guide Purpose of L2 Cache 2 The mode of processing which writes data in the physical disk while simultaneously writing data in the cache L2 Cache Types When binding an L2 cache select either of the following types for the L2 cache type e Read Write An L2 cache can be used as a read cache write cache or persistent write e Read only An L2 cache can be used as a read cache or persistent write The characteristics depending on the L2 cache configuration Type Redundancy Required Capacity To Fault Tolerance SSDs Be Decreased Read Write Duplication Two or Half e When one SSD went down more the L2 cache cannot be used continuously as a write cache but it can be used continuously as a read cache or persistent write e When two or more SSDs went down the L2 cache cannot be used continuously Read only None One or None When one or more SSDs went down more the L2 cache cannot be used continuously We recommended selecting 1 Read Write for the L2 cache type with the emphasis on fault tolerance L2 Cache Configuration An L2 cache is made up of an L2 cache pool that is configured on SSD and logical disks for L2 cache that are bound in the L2 cache pool By installing the L2 cache function to a disk array an L2 cache pool and logical disks fo
26. in the disk array detail information Cache State Cache Total Capacity L2 cache State L2 cache Total Capacity L2 cache Mode Operations of L2 Cache Performance Analysis This section describes operations for analyzing the performance of the L2 cache Performance Monitor and AutoTune can display the performance information relating to the L2 cache in the cache metrics Performance Monitor is capable of outputting the performance information about the L2 cache to a CSV file by means of a CSV conversion tool For details about the performance information to be output to a CSV file refer to the Performance Monitoring User s Manual AutoTune is capable of displaying the following performance information in graphs L1 L2 cache hit ratio Displays the ratio that read requests hit the L1 cache or L2 cache L2 cache page in size 10400410 002 11 2012 2012 Overland Storage Inc lt q 2 14 SnapSAN S5000 AutoCache User Guide L2 Cache Settings Displays the size of the data that have been transferred from the L1 cache to the L2 cache by page in operations L2 cache average dirty pages Displays the average ratio of pages including data which has not been written to a physical disk among write cache pages of the L2 cache This metrics can be displayed only when using the L2 cache of Read Write L2 cache maximum dirty pages Displays the maximum ratio of pages including data which has not been written to a physical disk
27. ings Step 4 Wait for complete stop of the L2 cache function Step 3 Start L cache unbind Step 6 Unbind the LI cache Step 7 End L cache unbind Step 8 Adda 58D Step 9 Start L2 cache bind Step 10 Bind an L2 cache Step 11 End L cache bind Step 12 Check the L cache state Figure 4 19 Procedure for Capacity Expansion Handling When L2 Cache Is Degraded This section describes the restoration procedure to be taken when a failure occurs in one physical disk composing the L2 cache and the redundancy of the L2 cache is lost after the redundant L2 cache is installed During restoration processing of the L2 cache the I O response sometimes declines Therefore it is recommended to implement work in the low time zone of the load 10400410 002 11 2012 2012 Overland Storage Inc lt 4 4 12 SnapSAN S5000 AutoCache User Guide Initial Configuration Step 1 Detect degradation of the L2 cache Step 2 Replace the faulty component Step 3 Check the L2 cache state Figure 4 20 Procedure to Be Taken When L2 Cache Is Degraded 1 Detect degradation of the L2 cache Since a message SnapSAN Manager07642 indicating that the L2 cache was degraded is displayed you can find that the L2 cache entered degraded state in other word the redundancy of the L2 cache was lost At the same time a message indicating that the state of the resource making up the L2 cache was changed 1s also displayed 2 Replace the faulty
28. out the L2 cache SnapSAN Manager Main Window The SnapSAN Manager main window on the SnapSAN Manager client displays the following information relating to the L2 cache in the disk array detail information 10400410 002 11 2012 2012 Overland Storage Inc lt q 2 13 SnapSAN S5000 AutoCache User Guide L2 Cache Settings Cache State Displays one of the following as the operating state of the cache modules installed in the unit Cache Total Capacity Displays the total physical capacity of the cache modules installed in the unit Cache module list Displays the information about the cache modules installed in the unit L2 cache State Displays the operating state of the pool used for the L2 cache L2 cache Total Capacity Displays the total capacity of physical disks used as the L2 cache L2 cache Mode Displays the L2 cache operation mode Pool list Displays the information about the pool used for the L2 cache Physical disk list Displays the information about the physical disks used for the L2 cache To judge whether or not it is an L2 cache pool with Pool list screen in the information list display area refer to the Type column If you want to display the Type column on right click the item name part and set the relevant item to be displayed Configuration Display Command SnapSAN Managerview The SnapSAN Managerview command can be used to display the following information relating to the L2 cache
29. owing L1 L2 Cache Hit Ratio 5 Change the analysis items In Configure Settings add the hit ratio Read Hit to the metrics to be displayed on a graph 10400410 002 11 2012 2012 Overland Storage Inc lt 4 4 4 SnapSAN 5000 AutoCache User Guide Initial Configuration Configure Settings xs Timeframe Resources Metrics pispaay Filter Metric1 Li L2 Cache Hit Ratio I O Type A To E Write E Read E To H E Write Hit Iv Read Hit F d Metric2 cache Hit Ratio I O Type E Total E Write Read Total Hit Write Hit V Read Hit Prefetch Read Hit Value for Analyze Iv Measured EB Maximum Ez Minimum r Note Select the Statistic Information type I O type Cap type and value for analyze a camer pete Figure 4 7 AutoTune Configure Settings 6 Execute advanced analysis The L1 L2 cache hit ratio and L1 cache hit ratio Read Hit are displayed on the same graph If the L2 L2 cache hit ratio is higher than the L2 cache hit ratio Read Hit in any time interval the L2 cache was efficiently used in the time interval Efficient use of the read cache of the L2 cache improves the response to read requests Cache Li L2 Cache Hit Ratio Cache Hit Hatin 10 03 2027 oo oo ao o7 2043 13 5 Hourly Jummary LI LZ Cache Hit Ratio 4 Cache Hit Ratio 4 Figure 4 8 AutoTune Graph Showing L1 L2 and L1 Cache Hit Ratio 10400410 0
30. pecify the number of physical disks SSDs and their capacity for the L2 Cache The number of physical disks i Auto disk selection Physical disk capacity Manual disk selection Select physical disks A to fi n rr Ce La Ge Figure 2 1 L2 Cache Set L2 cache type selection Select the type of the L2 cache to be bound e L2 cache type Select the type of the L2 cache The available types are e Read Write e Read only Number of physical disks and physical disk capacity Select the physical disks to be used e Auto disk selection Select the number of physical disks to be used and the capacity per physical disk The number of physical disks that can be used is Read Write 2 to 4 Read only 1 or 2 e Manual disk selection If you click the Select physical disks button you can manually select the physical disks to be used for the L2 cache Navigation button s lt q 2 3 SnapSAN S5000 AutoCache User Guide L2 Cache Settings e Next The Confirmation screen is displayed e Cancel A dialog box is displayed that asks if you want to end the wizard Clicking the OK button in the dialog box ends the wizard and displays the Monitor Screen Display screen e You cannot create another L2 cache if you have already created an L2 cache e SSD is the only physical disk type that can be used for L2 cache e You cannot use any of the physical disks numbered 0 to 3 that are installed on th
31. port metrics Step 2 Change the application settings Step 3 Change the quick analysis settings Step 4 Execute quick analysis Figure 4 14 Procedure for Checking for the Read Cache Usage Configure Quick Analysis Disk Array 2000000099 100001 Report TemplateSet gt Report Template eal Port H 0 H Host Director H 0 Replication Port Cache Cache Hit Ratio Total Write Read LiL Cache Hit Ratio Read LI Cache Page In Size Available Report Templates A Resource Metric Creator Add Save Load Edit Current Loading TemplateSet Update The Performance Analysis of the Storage Type Interval Period From 02 15 2012 09 47 to 02 16 2012 09 46 Mon Tue Wed Thu Fri Sat Sun cored te f Restrict Timeframe Figure 4 15 AutoTune Configure Quick Analysis Execute quick analysis 10400410 002 11 2012 2012 Overland Storage Inc 44 9 SnapSAN 5000 AutoCache User Guide Initial Configuration Execute Quick Analysis In this example it is executing the quick analysis by the hourly summary If the L2 cache page in size is large and L2 cache produces less effect it may be possible to use the read cache of the L2 cache more efficiently by increasing the L2 cache capacity Figure 4 16 AutoTune Graph Showing L2 Cache Page in Size Checking for the Write Cache Usage This section describes the procedure for checking for the usage of the write cache
32. r L2 cache are bound The following figure shows a configuration example when an L2 cache is bound L cache pool Logical disk for L2 cache 1 Logical disk for L2 cache 2 Logical disk for L2 cache 3 Figure 1 2 L2 Cache Configuration 10400410 002 11 2012 2012 Overland Storage Inc lt 4 1 2 SnapSAN 5000 AutoCache User Guide Purpose of L2 Cache L2 Cache Examples Improving Response Previously there were situations where operations centered on random access increased loads of HDD disks thereby having lowered response If you apply an L2 cache to such operations the response can be improved with HDD disks being accessed due to cache hit miss less frequently Reducing Operational Cost Regarding operations for which high response is required even when heavily loaded it has been a traditional method to evenly use as many HDD disks as possible to distribute loads However with this method requiring a large number of HDD disks for load distribution a major problem was that the power consumed during operations increased having raised the operational cost If you apply an L2 cache to operations like the above you can improve response by adding a few SSD disks instead of installing many additional HDD disks Compared with load distribution over HDD disks the use of L2 cache not only needs fewer additional physical disks but also saves power with physically moving parts being reduced thus enabling a substantial red
33. rs except to meet the purpose for which it was delivered It is understood that no right is conveyed to reproduce or have reproduced any item herein disclosed without express permission from Overland Storage Overland Storage provides this manual as is without warranty of any kind either expressed or implied including but not limited to the implied warranties of merchantability and fitness for a particular purpose Overland Storage may make improvements or changes in the product s or programs described in this manual at any time These changes will be incorporated in new editions of this publication Overland Storage assumes no responsibility for the accuracy completeness sufficiency or usefulness of this manual nor for any problem that might arise from the use of the information in this manual 10400410 002 11 2012 2012 Overland Storage Inc lt overland storage Preface This user guide explains how to install setup and use your new SnapSAN AutoCache for Windows software to analyze the causes of lowered responses in the disk array subsystem and improving its performances This guide assumes that you are familiar with computer hardware data storage and network administration terminology and tasks It also assumes you have basic knowledge of Internet SCSI GSCSJ Serial attached SCSI SAS Serial ATA SATA Storage Area Network SAN and Redundant Array of Independent Disks RAID technology This guide assumes that you
34. sk array in which the L2 cache was bound on the SnapSAN Manager client Confirm that the L2 cache state is normal 10400410 002 11 2012 2012 Overland Storage Inc lt 4 1 SnapSAN 5000 AutoCache User Guide Initial Configuration Confirming Effects of Read Cache Installation This section describes the procedure for checking that the read cache of the L2 cache is used effectively by using AutoTune after installing the read cache of the L2 cache It is assumed that the license for Performance Monitor is unlocked and accumulation of metrics of the disk array 1s started already Step 1 Import metrics Step 2 Change the application settings Step 3 Change the quick analysis settings Step 4 Execute quick analysis Step 5 Change the analysis items Step 6 Execute advanced analysis Figure 4 2 Procedure for Confirming Effects of Read Cache Installation Follow the procedure 1 Import metrics Collect the accumulated metrics of the disk array by using Performance Monitor Start AutoTune and in Import Data import the collected metrics of the disk array 2 Change the application settings To analyze the metrics of the caches change the resource and metrics type to Advanced mode in Application Settings of AutoTune and restart AutoTune If Advanced mode is set already this step 1s not necessary 10400410 002 11 2012 2012 Overland Storage Inc lt 4 4 2 SnapSAN S5000 AutoCache User Guide Initial Confi
35. ther m Figure 2 12 Confirmation Dialog Box If you click Yes the change of L2 cache settings is executed e Cancel The Monitor Screen Display screen is displayed without changing the settings L2 Cache On Off for Each Logical Disk You can set on off the L2 cache for each logical disk on the Change of Settings screen The Change of Settings screen consists of the following screen Change of Settings ig Change Of Settings 1 Select a logical disk that will be changed Logical disk list Number j Logical disk name Capacity Gel ooOO0Sh ZOO0D008S910000L10005 2 0 2000000099 100000068 2 0 CSVR_E 0008 80 0 z20000000SS1000010009 40 0 gt Configure the advanced settings Logical disk name z0000000391000010005 Logical disk type Read cache Enable Write cache Enable LZ Cache Enable ae F Use quota 1 39 Bobo s antares Actual pool capacity Total capacity of logical disks in the pool Use threshold 1 99 Accessbility of the logical disk Don t make an LD inaccessible m Figure 2 13 Change of Settings Logical disk selection Select a logical disk of which settings to be changed from the list 10400410 002 11 2012 2012 Overland Storage Inc lt q 2 12 SnapSAN S5000 AutoCache User Guide L2 Cache Settings Change the settings Change the settings as needed For the settings other than the
36. tton s e Finish The Monitor Screen Display screen is displayed Change of L2 Cache Settings You can change settings of the L2 cache The Change of Settings screen consists of the following screen Change of Settings Change settings of the L2 cache 10400410 002 11 2012 2012 Overland Storage Inc lt q 2 10 SnapSAN 5000 AutoCache User Guide L2 Cache Settings i Change Of Settings Enable or disable the L2 Cache mode Explanation To use the Lf Cache function enable the Le Cache mode When the Le Cache function is disabled data in LZ Cache if moved ta disks Before deleting a pool for Lz Cache and logical disks in it disable the LZ Cache mode Fool name Poo 10004 _L2CHE Logical disks for L Cache Logical disk name 1 Poo O004_L2CHEOFFE Logical disk name Z Poo 10004 _ L2CHEOFFE Logical disk name 3 Poo 10004 _L2CHEOFFF Explanation Pool name Specify the name of the pool for Le Cache Logical disk name Specify the names af the logical disks for Lz Cache Figure 2 11 Change of Settings If you want to change the L2 cache configuration such as the number of SSDs and the L2 cache type release the L2 cache once and then set it in creating an L2 cache Enable the L2 Cache mode By selecting this checkbox the L2 cache function is enabled By deselecting this checkbox the L2 cache function is disabled and unwritten data in the write cache and persistent write cache is written to a HDD
37. uction in the operational cost 10400410 002 11 2012 2012 Overland Storage Inc 41 3 overland J storage L2 Cache Function L2 Cache Settings The L2 cache function is divided into the following three e L2 cache settings e L2 cache information display e L2 cache performance analysis L2 cache settings involve the following functions L2 cache bind Use this function to create an L2 cache When L2 cache bind is executed an L2 cache pool and logical disks for L2 cache are configured and operation using the L2 cache is started L2 cache unbind Use this function to free the L2 cache When L2 cache unbind is executed the L2 cache pool and the logical disks for L2 cache are freed Change of L2 cache settings Use this function to stop and restart the L2 cache function and to change the nickname of the L2 cache pool or the logical disks for L2 cache Set on off the L2 cache for each logical disk Use this function to make the L2 cache enabled or disabled for each logical disk When executing the L2 cache unbind it is necessary to make an L2 cache function stop by the change of L2 cache settings beforehand Because the operation of the L2 cache stops when making an L2 cache function stop the response of I O sometimes declines The initial nicknames of the L2 cache pool and the logical disks for L2 cache are set according to the following naming rules L2 cache pool Poolxxxx_L2CHE logical disks for L2 cache Poolxxxx_L
38. unbound Number Capacity GB Type 00h 0016h 87 6 SSD 00h 0017h 87 6 SSD Figure 2 8 L2 Cache Unbind The physical disks in current use for the L2 cache are listed When the L2 cache function is enabled or the function is being disabled the L2 cache cannot be unbound It is necessary to disable the L2 cache function on the Change of Settings screen beforehand and unbind the L2 cache when the process is complete Navigation button s e Set The following confirmation dialog box is displayed eoe baian 1 Is it OK to start Le Cache Unbind a j Figure 2 9 Confirmation Dialog Box If you click Yes the L2 cache unbind operation is executed When the operation is successful the Completion screen is displayed e Cancel A dialog box is displayed that asks if you want to end the wizard Clicking the OK button in the dialog box ends the wizard and displays the Monitor Screen Display screen Completion The result of the L2 cache unbind is displayed 10400410 002 11 2012 2012 Overland Storage Inc lt 2 9 SnapSAN S5000 AutoCache User Guide L2 Cache Settings j L2 Cache Unbind Lz Cache Unbind gt Completion Click Finish to exit Monitoring of the disk array resumes Figure 2 10 L2 Cache Unbind Completion When this operation is successful the following link is displayed Bind L2 cache To bind an L2 cache start the L2 Cache Bind screen Navigation bu
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