IBM DS8000 manual Hot spot avoidance

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For example, in the zSeries environment, the RMF™ RAID rank report can be used to investigate RAID rank saturation when the DS8000 is already installed in your environment. New counters will be reported by RMF that will provide statistics on a volume level for channel and disk analysis.

In an open system environment the iostat command is useful to determine whether a system’s I/O load is balanced or whether a single volume is becoming a performance bottleneck. The tool reports I/O statistics for TTY devices, disks, and CD-ROMs. It monitors I/O device throughput and utilization by observing the time the disks are active in relation to their average transfer rates. The vmstat utility may also be used to take a quick snapshot or overview of the system performance.

9.6.8 Hot spot avoidance

Workload activity concentrated on a limited number of RAID ranks will saturate the RAID ranks. This may result in poor response times, so balancing I/O activity across any disk system is important. Spreading your I/O activity evenly across the available DS8000s will enable you to optimally exploit the DS8000 resources, thus providing better performance. I/O activity attributes to consider include spreading I/O activity across:

The two servers of the DS8000

The loops of the DS8000

All available RAID ranks

Across multiple DS8000s

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Contents IBM TotalStorage DS8000 Series Page IBM TotalStorage DS8000 Series Concepts and Architecture First Edition April Contents Page Benefits of virtualization Vi DS8000 Series Concepts and Architecture Summary Viii DS8000 Series Concepts and Architecture Page Page Index Xii DS8000 Series Concepts and Architecture Copyright License Trademarks DfsortPreface Team that wrote this redbookXvi DS8000 Series Concepts and Architecture Preface Xviii DS8000 Series Concepts and Architecture Become a published author Comments welcomeXx DS8000 Series Concepts and Architecture Part 1 Introduction DS8000 Series Concepts and Architecture Introduction to the DS8000 series Infrastructure Simplification DS8000, a member of the TotalStorage DS familyOverview of the DS8000 series Business ContinuityDS8000 Base frame Hardware overview Storage Hardware Management Console S-HMC for the DS8000 Storage capacityStorage system logical partitions LPARs IBM Standby Capacity on Demand offering for the DS8000Supported environments Resiliency Family for Business ContinuityIBM TotalStorage FlashCopy IBM TotalStorage Metro Mirror Synchronous PprcInteroperability Service and setupThree-site solution IBM TotalStorage Global Mirror Asynchronous PprcPositioning Common set of functionsDS8000 compared to ESS DS8000 compared to DS6000 IBM TotalStorage DS Command-Line Interface DS CLICommon management functions IBM TotalStorage DS Storage ManagerScalability and configuration flexibility Future directions of storage system LPARsDS Open application programming interface IBM TotalStorage Multipath Subsystem Device Driver SDD Sequential Prefetching in Adaptive Replacement Cache SarcPerformance Performance for zSeriesSummary 16 DS8000 Series Concepts and Architecture Part 2 Architecture 18 DS8000 Series Concepts and Architecture Components Frames Base frameExpansion frame Rack operator panelArchitecture Rack operator panelSAN fabric Server-based SMP design Cache managementComponents Processor complex RandomseqComponents Rear view Service processor and SpcnFront view Processor memoryRIO-G 2 I/O enclosuresDisk subsystem Rear viewDevice adapters Disk enclosures DS8000 device adapterNon-switched FC-AL drawbacks DS8000 disk enclosureSwitched FC-AL advantages 11 DS8000 disk enclosureDS8000 switched FC-AL implementation 12 Disk enclosure switched connectionsExpansion Arrays and spares14 DS8000 switched loop layout Arrays across loopsHost adapters AAL benefitsDDMs Escon distances Ficon and Fibre Channel protocol host adaptersControl units and logical paths Remote Mirror and Copy with EsconFibre Channel supported servers Power and coolingRack Power Control cards RPC Fibre Channel distancesDisk enclosure power and cooling Primary power suppliesProcessor and I/O enclosure power supplies Battery backup assembliesEthernet switches 42 DS8000 Series Concepts and Architecture Storage system LPARs Logical partitions Partitioning concepts Introduction to logical partitioningVirtualization Engine technology PartitionsBuilding block Physical partitioning PparLogical partitioning Lpar Micro-Partitioning Software and hardware fault isolationDynamic logical partitioning Virtual I/OProduction and test environments Why Logically Partition?Server consolidation Application isolationDS8000 and Lpar Lpar and storage facility imagesIncreased flexibility of resource allocation 2 DS8300 Lpar implementation DS8300 Model 9A2 Lpar and storage facility imageStorage facility image hardware components DS8300 Lpar resource allocationStorage Facility Image Processor complex Processor and memory allocations4 DS8300 Model 9A2 configuration options RIO-G interconnect separationDS8300 example configuration Model conversionLpar security through Power Hypervisor Phyp Model conversions regarding Lpar functionalityLpar and Copy Services Lpar protection Power HypervisorLpar benefits FlashCopyRemote mirroring Storage system LPARs Logical partitions Addressing capabilities with storage facility images Example of storage facility images in the DS8300DS8300 addressing capabilities 60 DS8000 Series Concepts and Architecture RAS Storage unit NamingStorage complex Storage facility imageProcessor complex RAS Processor complexReliability, availability, and serviceability Permanent monitoringMemory reliability, fault tolerance, and integrity Self-healing+1 redundancy Hypervisor Storage image independence Fault maskingConcurrent Maintenance Resource deallocation2 I/O enclosure Server RASRIO-G a self-healing interconnect Metadata checksServer failover and failback Data flowFailover Normal data flowNVS recovery after complete power loss FailbackHost connection availability Single or multiple pathEnclosure SAN/FICON/ESCON switches Multi-pathing softwareOpen systems host connection ZSeries host connectionSwitched disk connections Disk path redundancyRAID-5 theory RAID-5 overviewRAID-10 overview RAID-5 implementation in the DS8000Spare creation RAID-10 theoryRAID-10 implementation in the DS8000 Predictive Failure Analysis PFA Floating sparesHot plugable DDMs Disk scrubbing Battery backup unitsRack power control card RPC Rack cooling fansPower control of the DS8000 Building power lossPower fluctuation protection Emergency power off EPOMicrocode updates Installation processManagement console HMC considerationsDifferent code versions across storage images Virtualization concepts Virtualization definition Storage system virtualizationAbstraction layers for disk virtualization Storage Facility virtualizationArray sites Physical layer as the base for virtualizationArrays Array siteRanks Creation of an arrayExtent pools Forming an FB rank with 1 GB extentsServer0 Logical volumes CKD volumesFixed Block LUNs Volume with Allocation and deletion of LUNs/CKD volumes ISeries LUNsLogical subsystems LSS DB2 Volume access Address groupsVolume group Host attachment11 Host attachments and volume groups Summary of the virtualization hierarchyPlacement of data 12 Virtualization hierarchy13 Optimal placement of data Benefits of virtualization101 102 DS8000 Series Concepts and Architecture IBM TotalStorage DS8000 model overview and scalability 103DS8000 highlights Model naming conventions2 DS8100 Model Maximum configuration for the Model 3 DS8300 Models 922 and 9A2IBM TotalStorage DS8000 model overview and scalability Model comparison Large and scalable capacity Designed for scalabilityScalability for capacity DS8000 model comparisonFuture plan Scalability for performanceAdding DDMs Comparison of models for capacityWay I/O controllers Linear-scalable architectureRIO-G Benefit of the DS8000 for scalabilityModel upgrades Model conversions114 DS8000 Series Concepts and Architecture Copy Services 115Introduction to Copy Services Copy Services functionsPoint-in-Time Copy FlashCopy Read from the source volume Read from the target volumeWrite to the source volume FlashCopy options Point-in-Time Copy function authorizationRefresh target volume also known as Incremental FlashCopy No background copy optionData Set FlashCopy Incremental FlashCopyMultiple Relationship FlashCopy Data Set FlashCopyWhat is Consistency Group FlashCopy? Consistency Group FlashCopyFlashCopy to Pprc Primary Volume FlashCopy Source Volume FlashCopy Target VolumePersistent FlashCopy Inband Commands over Remote Mirror linkRemote Mirror and Copy Peer-to-Peer Remote Copy Metro Mirror Synchronous PprcGlobal Copy PPRC-XD Metro MirrorGlobal Mirror Asynchronous Pprc Global CopyHow Global Mirror works Global MirrorGlobal Mirror How it works OS Global Mirror XRC Secondary server 11 z/OS Global MirrorComparison of the Remote Mirror and Copy functions 12 z/OS Metro/Global MirrorGlobal Copy PPRC-XD What is a Consistency Group? What is data consistency?How does Consistency Group keep data consistency? 1st LSS13 Interfaces for Copy Services Storage Hardware Management Console S-HMC16 DS8000 Copy Services network components DS Storage Manager Web-based interfaceDS Command-Line Interface DS CLI Tip What is changed from the ESS CLI?DS Open application programming Interface API Interoperability with ESS Future Plans140 DS8000 Series Concepts and Architecture Part 3 Planning and configuration 141142 DS8000 Series Concepts and Architecture Installation planning 143Packaged dimensions and weight for DS8000 models General considerationsDelivery requirements Installation site preparation Floor and space requirements145 Installing on raised or nonraised floors Meeting floor load requirementsCalculating space requirements DS8000 dimensions Power requirementsPower control 147Power outlet requirements Input voltage requirementsEnvironmental requirements Power connector requirementsPower consumption and environmental information Fans and air intake areasHost attachment Attaching to open systems hostsCooling the storage complex ESCON-attached S/390 and zSeries hosts FICON-attached S/390 and zSeries hosts151 Where to get the updated information for host attachment Host systems attachmentSAN Fabric products Channel extension technology products Network and SAN requirementsHMC network requirements 153Remote power control requirements Remote support connection requirementsSAN requirements 155 156 DS8000 Series Concepts and Architecture Configuration planning 157Configuration planning overview Storage Hardware Management Console S-HMCS-HMC and Ethernet switches External S-HMCRemote services HMC software componentsDS Storage Manager 161 Required portsHMC network topology Dial-up connection Secure high-speed connection163 Remote access Call homeSecurity mechanism 2 Public key encryption HMC security considerationsSecurity mechanism 1 Console must initiate session 165Security mechanism 3 Login security FTP Offload optionHMC user management DS8000 licensed functions Operating environment license OEL required featureLicensed function indicators 167Point-in-Time Copy function 2244 Model PTC Optional featuresOperating environment license feature codes License scope for each DS8000 licensed functionRemote Mirror and Copy functions 2244 Model RMC Point-in-Time Copy PTC feature codesRemote Mirror and Copy RMC feature codes Remote Mirror for z/OS 2244 Model RMZParallel Access Volumes PAV feature codes Parallel Access Volumes 2244 Model PAVRemote Mirror for zSeries RMZ feature codes Ordering licensed functions171 User authorize to FlashCopy 25 TB of CKD dataSolution Disk storage feature activation 173Scenarios for managing licensing Logical configurationsCapacity planning Adding storage capacity to an existing licensed function175 CKD RAID rank capacitySparing rules FB RAID rank capacitySparing examples 177Sparing Example 2 RAID-10 179 11 Sparing example 3 RAID-5 Different capacity, same RPMSparing Example 4 RAID-5 IBM Standby Capacity on Demand Standby CoDCapacity and well-balanced configuration 181DDM to DA Mapping -- 2-way Data migration planning 183Software packages Basic commandsOperating system mirroring Remote copy technologiesMigration services and appliances 6 z/OS data migration methods185 Planning for performance 15 Different data migration methodsSize of cache storage Parallel Access Volumes z/OS onlyDisk Magic Number of host ports/channelsHot spot avoidance DS Storage Manager logical configuration 189Configuration hierarchy, terminology, and concepts Storage configuration terminologyPSeries1 PSeries2 Ranks Array sitesArrays Extent poolsExtent Pool Logical volumes Volume groupsVolume Group Host System C Address groupsExtent Pool Extent Pool Planning Raw or physical DDM layer Array site layerArray layer Rank layer Logical Configuration flowLogical volume layer Extent pool layerIntroducing the GUI and logical configuration panels Connecting to the DS800010 Entering the URL using the TCP/IP address for the S-HMC Welcome panelReal-time Manager configuration 12 The Welcome panelCopy Services Simulated Manager configurationCreating and defining the users and passwords LogUsing the help panels information center 15 User administration panelNavigating the GUI 17 View of the information center19 View of the storage complexes in the work area 20 View of the Storage Complexes sectionRadio buttons and check boxes 21 Storage unit view of the pull-downLogical configuration process Configuring a storage complexConfiguring the storage unit 25 The General storage unit information panel Configuration advancement steps 28 Specify I/O adapter configuration panel Configuring the logical host systems 29 Create host systems, screen31 View of the General host information panel 33 Define host ports panel, with updated host information Creating arrays from array sites Click Apply assignment and OK36 The Definition method panel Creating extent pools 38 The Add arrays to ranks panel with FB selectedCreating FB volumes from extents 39 The Definition method panel42 The Define volume properties panel 41 The Select extent pool panelCreating volume groups Click Volume Groups44 The Define volume group properties filled out Deleting LUNs and recovering space in the extent pool Assigning LUNs to the hostsClick Host Systems Creating CKD LCUs Creating CKD volumesClick Volumes → zSeries Click FinishDisplaying the storage unit Wwnn Click Storage Units49 View of the Wwnn in the General panel 230 DS8000 Series Concepts and Architecture 231 Introduction FunctionalityInstallation methods Supported environmentsCommand flow ESS Copy Services command flow using ESS Copy Services CLIDS CLI command flow Secure socketsTCP/IP ports DS6000 command flow DS8000 split networkCommand flow for the DS6000 ESS CLI co-existenceStorage management CLI co-existenceExample 11-1 Using DS CLI via a single command Command modesSingle command mode User securityExample 11-4 Using DS CLI in interactive mode Interactive modeScript mode Example 11-3 Creating a DS CLI scriptSyntax conventions Lists all available DS CLI commandsLists all DS CLI commands with syntax information User assistanceMan pages Example 11-8 Use of the help -lcommandReturn codes DS CLI return codesExample 11-11 Example of a configuration script Usage examplesExample 11-10 Return code examples Which CLI to use based on what hardware you have installed Mixed device environments and migrationDetermining the saved tasks to be migrated DS CLI migration exampleMigration tasks Migration considerationsA portion of the tasks listed by using the GUI Collecting the task detailsConverting the saved task to a DS CLI command Using the GUI to get the contents of a FlashCopy taskExample 11-14 Using interactive dscli mode without profiles Converting a FlashCopy task to DS CLISetting up a profile Using DS CLI commands via a single command or scriptProcedure to create an encrypted password file Creating a user ID for use only with ESSIssuing a DS CLI command and scripting it Example 11-18 Establishing a FlashCopy with a single commandExample 11-20 Using script mode Example 11-19 Creating an executable file252 DS8000 Series Concepts and Architecture Performance considerations 253What is the challenge? Speed gap between server and disk storageNew and enhanced functions Where do we start? 255Arrays across loops Switch from Escon to Ficon portsSSA backend interconnection Pprc over Fibre Channel linksFC-AL shortcomings Fibre Channel switched disk interconnection at the back endHow does the DS8000 address the challenge? How the DS8000 series overcomes FC-AL shortcomingsMemory 259 Fibre Channel device adapter New four-port host adaptersPOWER5 Heart of the DS8000 dual cluster design 261RIO-G Interconnect RIO-G Interconnect 263Performance and sizing considerations for open systems Vertical growth and scalabilityCache size considerations for open systems Workload characteristicsData placement in the DS8000 265LVM striping 266 DS8000 Series Concepts and ArchitectureStripe size 267Determining where to attach the host Determining the number of paths to a LUNSubsystem Device Driver SDD Dynamic I/O load-balancing Performance and sizing considerations for z/OS Connect to zSeries hosts269 Performance potential in z/OS environments 12 DS8100 frontend connectivity example partial viewAppropriate DS8000 size in z/OS environments Processor memory size considerations for z/OS environments271 Or zSeries channel consolidation Disk array sizing considerations for z/OS environments 273Configuration recommendations for z/OS Configure one extent pool for each single rankMinimize the number of extent pools 275Extent pool0 Extent pool1 Plan for a reasonable number of extent pools277 15 Mix of extent pools278 DS8000 Series Concepts and Architecture 279 280 DS8000 Series Concepts and Architecture ZSeries software enhancements 281Software enhancements for the DS8000 13.2 z/OS enhancementsScalability support Benefits of the scalability enhancements Large Volume Support LVSRead availability mask support 283Initial Program Load IPL enhancements 13.2.5 DS8000 definition to host softwareRead control unit and device recognition for DS8000 New performance statistics 285Listdata Count 287 Listdata Counts report of DS8000Listdata Status Resource Management Facility RMF 289Migration considerations 13.3 z/VM enhancements13.4 z/VSE enhancements Coexistence considerationsTPF enhancements 291292 DS8000 Series Concepts and Architecture Data migration in zSeries environments 293Define migration objectives in z/OS environments Consolidate storage subsystemsConsolidate logical volumes Considerations for new logical volume size295 Dynamic Parallel Access Volumes required for large volumes Example 14-1 Data Classes with EF attributeKeep source and target volume size at the current size 297Data migration based on physical migration Summary of data migration objectivesPhysical migration with DFSMSdss and other storage software Software- and hardware-based data migration Data migration with Piper for z/OS299 Piper hardware Data migration with z/OS Global Mirror 301Hardware- or microcode-based migration Bridge from Escon to Ficon with Metro/Global CopyData migration with Metro Mirror or Global Copy 303Pprcopy DDNAMEDD02 Query 305 Example 14-3 All data is replicated491 Example 14-5 All data is replicatedData Set Services Utility Data migration based on logical migration307 Hierarchical Storage Manager, DFSMShsm System utilities309 SMS Storage Groups migration source environmentExample 14-8 Select SMS storage group in Scds Storage Group Application SelectionAlter Volume Statuses Pool Copy Pool Backup only 311Example 14-12 Confirmation about SMS volume status change ALL Volumes Altered313 Combine physical and logical data migration 14.5 z/VM and VSE/ESA data migration Summary of data migration315 316 DS8000 Series Concepts and Architecture 317 318 DS8000 Series Concepts and Architecture Open systems support and software 319Where to look for updated and detailed information Open systems supportSupported operating systems and servers DS8000 Host Systems Attachment Guide DS8000 Interoperability MatrixIBM HBA Search Tool TotalStorage Proven programEmulex Corporation Differences to the ESSPlatform and operating system vendors’ pages AttoBoot support Additional supported configurations RPQSubsystem Device Driver Other multipathing solutions DS CLIIBM TotalStorage Productivity Center IBM TotalStorage Productivity CenterMDM main panel Device Manager Sample Device Manager viewTPC for Disk Sample screenshot of TPC for DiskGlobal Mirror Utility TPC for ReplicationEnterprise Remote Copy Management Facility eRCMF 332 DS8000 Series Concepts and Architecture Data migration in the open Systems environment 333Tor Comparison of migration methods Host operating system-based migrationBasic copy commands Copy raw devicesMigration using volume management software Online copy and synchronization with rsyncBackup and restore Migration using LVM mirroringMigration using backup and restore Subsystem-based data migrationMetro Mirror and Global Copy Combination of Metro Mirror and Global CopyIBM Piper migration Piper migrationIBM migration services Other migration applicationsAppendix A. Open systems operating systems specifics 343Planning Data placement considerationsDS8000 Host Systems Attachment Guide Capacity planning considerationsUnix performance monitoring tools IostatExample A-1 AIX iostat output System Activity Report SAR Example A-2 SUN Solaris iostat outputVmstat Example A-3 SAR Sample OutputFinding the World Wide Port Names Other publicationsAIX host attachment scripts Example A-4 Finding Fibre Channel adapter WWNManaging multiple paths Determine the installed SDD levelUseful SDD commands Subsystem device driver SDDExample A-7 lsvpcfg command Multipath I/O MpioDetermine the installed Sddpcm level Useful Mpio commandsExample A-8 lspath command result LVM striping LVM configurationAIX access methods for I/O LVM mirroringDirect I/O Boot device supportAIX on IBM iSeries Concurrent I/OFilemon Monitoring I/O performanceIostat Example A-9 Filemon output fileIBM Mpio FC Linux Linux with zSeries and ESS Essentials Existing reference materialImplementing Linux with IBM Disk Storage Getting Started with zSeries Fibre Channel ProtocolImportant Linux issues Some Linux Scsi basicsTable A-1 Major numbers and special device files Missing device files Example A-10 Create new special device files for Scsi disksManaging multiple paths Limited number of Scsi devicesScsi device assignment changes RedHat Enterprise Linux RH-EL multiple LUN support Fibre Channel disks discovered before internal Scsi disksAdding FC disks dynamically Example A-12 Sample /etc/modules.confExample A-13 SCSi disks attached at system start time Linux on IBM iSeries Gaps in the LUN sequenceTroubleshooting and monitoring /proc pseudo file systemExample A-16 Sample /proc/scsi/scsi file Performance monitoring with iostat Generic Scsi toolsExample A-17 Sample /proc/scsi/qla2300/x HBA and operating system settings Microsoft Windows 2000/2003SDD for Windows Windows Server 2003 VDS support Figure A-1 Microsoft VDS ArchitectureHP OpenVMS FC port configurationVolume Shadow Copy Service Geographically Dispersed SitesVolume configuration ConfigurationsCommand Console LUN OpenVMS volume shadowingAppendix A. Open systems operating systems specifics 372 DS8000 Series Concepts and Architecture Appendix B. Using DS8000 with iSeries 373Supported environment Logical volume sizesTable B-1 OS/400 logical volume sizes HardwareProtected versus unprotected volumes Changing LUN protectionAdding volumes to iSeries configuration Using 5250 interfaceFigure B-3 Work with Disk Configuration menu Adding volumes to an Independent Auxiliary Storage Pool Figure B-5 Confirm Add UnitsFigure B-7 iSeries Navigator Signon to iSeries window Figure B-9 SST Signon Figure B-11 New disk pool welcome Figure B-13 Confirm disk pool configuration Figure B-15 Choose the disks to add to the Disk Pool Figure B-17 New Disk Pool Summary Figure B-20 New Disk Pool shown on iSeries Navigator Multipath Avoiding single points of failureConfiguring multipath Figure B-22 Single points of failureAdding multipath volumes to iSeries using 5250 interface Figure B-24 Example of multipath with iSeriesFigure B-25 Adding multipath volumes to an ASP Adding volumes to iSeries using iSeries Navigator Figure B-27 Adding a multipath volumeFigure B-28 New Disk Pool shown on iSeries Navigator Managing multipath volumes using iSeries Navigator Figure B-30 Example of multipath logical unitsAppendix B. Using DS8000 with iSeries Figure B-32 Multipath logical unit properties Multipath rules for multiple iSeries systems or partitions Figure B-33 Multipath connectionsSizing guidelines Changing from single path to multipathPlanning for arrays and DDMs CacheNumber of iSeries Fibre Channel adapters Size and number of LUNsTable B-2 Capacity per I/O Adapter Recommended number of ranks Sharing ranks between iSeries and other serversTable B-3 Disk operations per second per RAID rank OS/400 mirroring Connecting via SAN switchesMigration Metro Mirror and Global CopyFigure B-35 Using Metro Mirror to migrate from ESS to DS8000 OS/400 data migrationFigure B-36 Ending allocation for existing disk units Copy Services for iSeries FlashCopyRemote Mirror and Copy ISeries toolkit for Copy Services AIX on IBM iSeriesLinux on IBM iSeries 406 DS8000 Series Concepts and Architecture Appendix C. Service and support offerings 407IBM Implementation Services for TotalStorage disk systems IBM Web sites for service offeringsIBM service offerings IBM Implementation Services for TotalStorage Copy FunctionsIBM Geographically Dispersed Parallel Sysplex Gdps Enterprise Remote Copy Management Facility eRCMFIBM Operational Support Services Support Line IBM eServer iSeries Copy ServicesAppendix C. Service and support offerings 412 DS8000 Series Concepts and Architecture IBM Redbooks Other publications413 Online resources How to get IBM Redbooks Help from IBM416 DS8000 Series Concepts and Architecture Index 417DS CLI OEL Escon Ficon RH-EL BBU Spcn VSE IBM TotalStorage DS8000 Series Concepts and Architecture Page Page IBM TotalStorage DS8000 Series Concepts Architecture

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