Using EMC Storage Array Technologies for Fast and ... - VMware

Why are data migrations performedTechnology refreshStorage consolidation and upgradePerformance tuningTo enable tiered storage (ILM)

Migration Challenges Facing Today’s Businesses24 x 7 x 365 application availabilityNo downtime windowsNo data exposurePerformance optimizationLoad balancing and volume resizingStorage utilizationComplexity and costDisparate systemsManual processesLong planning cyclesRisks

Type of data migrationsBackup and restoreHost based data migrationESX Server level migrationVirtual Machine migrationMigrations using SAN or IPStorage virtualization (Invista, SVC etc.)Migrations across heterogeneous storage arrays• Open Replicator• SAN CopyMigration between homogeneous storage arrays• CLARiiON to CLARiiON (MirrorView)• Symmetrix to Symmetrix (SRDF)• Celerra to Celerra (Celerra Replicator)

Host Based MigrationService Console can be used to perform migrationsCopy each virtual machines disks from source to target volumeCan be done using the “cp” command• Not practical for ESX 3.x environments“vmkfstools” in ESX 3.x environment provides an option to copy data• Not practical for ESX 2.x environmentsMigrations using Virtual Center“Cold” migrate can be used to move dataMigrations inside the Virtual MachinesHost based replication software• Open Migrator/LM for Windows and Linux• Replistor for WindowsLogical Volume Managers can “move” data

Using “cp” on ESX 2.5 Service ConsoleSteps needed to perform migrationPresent “source” and “target” disk(s) to ESX ServerCreate VMFS on “target” disk(s) and assign an appropriate labelPower virtual machines offUse “cp” to copy virtual disks from source VMFS to target VMFSRemove access to “source” disk(s)Rescan the SAN fabricRe-label the VMFS on “target” disk(s) to the original labelPower on virtual machinesIf “source” VMFS does not have labels, configuration files will need to bechangedMigration of individual VMs on the “source” VMFS can be performedWill need changes to the configuration files

Listing of Source and Target VMFS

Determining the Location and Name of Virtual Disks

Performing Migration using “cp” on Service Console

Completing the Swap of Source and Target VMFS

Migrations for ESX 3.x Using Service ConsoleData migration in ESX 3.x environment is more complex than ESX 2.xenvironmentVC is tightly integratedDifficult to perform data migration just using service consoleVC maintains significant information that is not deleted without manualinterventiondMotion can be usedCurrently supported for live upgrades from ESX 2.5 to ESX 3.0.1Large data migrations in ESX 3.x environments can get complexIf provided the choice:• First perform data migration in ESX 2.x environment• Then upgrade ESX 2.x to ESX 3.0 environment

Using “vmkfstools” on ESX 3.x Service ConsoleSteps needed to perform migration:Present “source” and “target” disk(s) to ESX ServerCreate VMFS on “target” disk(s) and assign an appropriate label• Use VC to create VMFS since it automatically aligns VMFS volumesCreate directories on “target” VMFS to match “source” VMFSCopy configuration files from “source” VMFS to “target” VMFSPower virtual machines offCopy virtual disks using “vmkfstools”Remove access to “source” disk(s) and rescan the SAN fabricUn-register virtual machines from VCDelete “source” VMFS information from VC databaseRe-label “target” VMFS to original “source” VMFS label nameRe-register VMs and power them on

Presenting Target Volumes to ESX 3.x

Migrating Data from Source to Target for ESX 3.x

Un-registering VMs using VC 2.x

Removing Access to Source VMFS

Removing Source VMFS Information on ESX 3.x

Removing Source VMFS from VC 2.x Database

Rename Target VMFS to Original VMFS Name

Register and Power on VM from New Disks

Advantages and Disadvantages of Using COSAdvantagesSimple to useFlexible– migration can be performed at individual virtual disk levelStorage Agnostic– “source” disks could be internal disks!DisadvantagesProtracted outagesSlow, cumbersome processCan use only processor 0 for migrating the data• No parallelism even on a large multi-processor server

Migration between homogeneous storage arraysHost based replication is an option (either at VM or ESX Server layer)Storage agnosticCan be used for migration to the same type of arraySymmetrix to SymmetrixCLARiiON to CLARiiONCelerra to CelerraSRDF for SymmetrixMirrorView for CLARiiONCelerra Replicator for CelerraCelerra Replicator is used for replicating NAS datastores on CelerraNetwork File Server

Advantages & DisadvantagesAdvantages:Highly scalable and fastDoes not consume host resources for migrationMinimal disruption to production hosts (both ESX Servers and VM)Enables incremental updates and testing before cut overSame process can be used to migrate other operating systemDisadvantages:Requires same type of array (array dependent)Cannot/difficult to change volume configuration when migrating dataCannot migrate at individual VM level

Migration between heterogeneous storage arraysHost based replication is an option (either at VM or ESX Server layer)Storage agnosticStorage Array based softwareOpen ReplicatorSAN CopyOpen Replicator and SAN Copy will be the focus for rest of thepresentation

EMC Open Replicator for DMXRuns entirely within DMX arrayExisting hardware and networkMounts open systems remotevolumesAppears as a host to remotestorageShares front-end FC portsPerforms raw block I/ORead, Write and IncrementalUpdate16 copies per session512 concurrent sessionsSymmetrixSANIBMCLARiiONHPQHitachi

EMC Open Replicator Modes of OperationPoint-in-Time BCV PushPoint-in-Time “Live” PushSTDBCVTargetTargetSTDStart: 6:00 a.m.End: 6:02 a.m.TargetTargetImage:6:00 a.m.Point-in-Time Volume Pull“Live” Data Migration PullTargetTargetTargetSTDSTDSTDSTDSTDOldOld

SAN Copy for CLARiiON ArraysFastCopies data between arraysFull and incremental copiesBi-directionalArray-based• No server or LAN impactsSimpleSingle point of managementScripted automationNo additional hardwareOpenApplication- and operating systemindependentCLARiiON, Symmetrix, and thirdpartysystemsSymmetrixSAN/WANIBMHitachiHP

SAN Copy for CLARiiON ArraysCLARiiON arrays capable of hostingSAN Copy:CX3-80, CX3-40, CX3-20, CX700,CX500, CX600, and CX400Full or incremental copies of dataresiding on a SAN Copy-hosted arraycan be “pushed”To any EMC or supported thirdpartyarrayFull copies of data residing on anysupported array can be “pulled” to aSAN Copy-hosted arraySourceDestinationPushPullDestinationSource

Using Open Replicator with ESX 2.xOpen Replicator is managed via CLI or GUIManagement can be performed from any supported platformOpen Replicator can be used to migrate RDM volumesOpen Replicator can be used to migrate VMFS volumesAll members of a spanned VMFS needs to migrated togetherAll virtual machines on a VMFS needs to be migrated at the same timeIncremental push capability of Open Replicator reduces downtime dramaticallyIf VMFS labels are used no reconfiguration of virtual machines is neededOpen Replicator is highly scalableThe whole environment can be migrated in one small outage windowSteps involved when migrating data from or to DMXZone the DMX ports to provide access to the third party storage array portsUse LUN masking software to provide DMX ports access to the appropriateLUNs

Migrating Data from DMX in ESX 2.x EnvironmentWhen migrating from DMX to supported third party storageCreate session that defines relationship between DMX LUNs and thirdparty storage LUN• If needed set it up for incremental refreshesActivate the session to obtain a point in time image of the dataTo minimize impact control the rate at which the data is copiedRecreate the session to perform incremental pushActivate the recreated session to obtain new point in time imageRepeat the steps above until the amount of data to be migrated is smallShutdown the virtual machines and start the final pushChange LUN masking so the ESX Servers have access to new LUNs• Remove access to the original LUNsRescan for new LUNsRestart the virtual machines as soon the Open Replicator sessioncompletes

Identifying the Devices to be Migrated

Determining Storage Array Volumes to be Migrated

Providing DMX Access to Remote Storage Devices

Creating and Activating Open Replicator Session

Tuning Open Replicator Sessions

Effect of Setting Ceiling on Migration

Querying Status of Sessions

Differential Push of Data

Benefits of Using Incremental Push

Changing ESX Server Access to Volumes

Finishing the Migration

Starting Virtual Machines on Migrated Volumes

Migrating Data to DMX in ESX 2.x EnvironmentWhen migrating to DMX from supported third party storage1. Create session that defines relationship between DMX LUNs and thirdparty storage LUNa. If available, ensure donor update is turned on2. Shutdown the virtual machines3. Activate the session to start migration of the data4. Change LUN masking so the ESX Servers have access to new LUNsa. Remove access to the original LUNs5. Rescan for new LUNs6. Restart the virtual machines as soon as possiblea. Data migration continues in the backgroundThe outage time is approximately the time required for step 2—5 listedabove

SAN Copy for Migrating ESX Server EnvironmentsSAN Copy is managed via CLI or GUISAN Copy is very similar to Open Replicator except forCannot support as many concurrent migrations as Open ReplicatorInitial push cannot provide a consistent point in time copy of the dataOne has to wait for pull to complete before accessing dataDoes not have donor update featureAll virtual machines on a VMFS needs to be migrated at the same timeIncremental push capability of SAN Copy reduces downtimedramaticallySAN Copy can provide much faster migration than what can be obtainedwith host based softwareSteps involved when migrating data from or to CLARiiON is the same aslisted for Open Replicator

Advantages & DisadvantagesAdvantages of using storage array based SAN migration softwareScalable and fast migration ratesAmount of downtimeIncremental refresh capabilitiesTest before you actually swap (leveraging storage array based snaps)No host cycles involvedDisadvantages of using storage array based SAN migration softwareCannot migrate a subset of virtual disksCan be more complex than using host based utilitiesRequires both source and target storage on the SAN

When to use what technologies for migrationOpen Replicator and SAN Copy are ideal when:Large amount of data (100+ GB) needs to be migratedMigration involves 10 or more virtual machinesEnvironments that do not have a large maintenance windowMigration is between dissimilar arrays (one of them is DMX or CLARiiON)Use Open ReplicatorWhen migrating data from DMX to supported third party arraysWhen migrating data to DMX from other supported arrays (exceptCLARiiON)Use SAN CopyWhen migrating data from CLARiiON to supported third party arraysCan be used for migrating data to CLARiiON but outage windows wouldbe largerUse host based utilities when migrating small amount of data or VM

AcknowledgmentsMike McGhee, Symmetrix EngineeringSusan Young, VMware InstructorSheetal Kochavara, CLARiiON EngineeringJeff Bernard, Alliance Manager

References“Best Practices for deploying VMware ESX 3.x and 2.5.x server withEMC Storage products” at VMworld 2006VMware ESX Server Using EMC Symmetrix Storage SystemsVMware ESX Server Using EMC CLARiiON Storage SystemsCLARiiON Integration with VMware ESX Server

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