HP P6000 manual Snapshots, Snapshot types, Snapshot guidelines, Monitoring snapshot space

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Snapclones cannot be created when the disk to be replicated is:

•A snapshot

•A disk that has a snapshot or mirrorclone

•In the process of normalizing (snapclone in progress) or being deleted (P6000 Command View running XCS 10000000 or earlier)

See also, “Optimizing snap creation” (page 40).

Snapshots

A snapshot is a dependent point-in-time copy of a virtual disk. It is dependent because data is not actually copied to the snapshot until it is overwritten on the source. Use snapshots when you need temporary copies; for example, to create a copy of a database that you then store on tape.

Snapshot types

Snapshot types are defined by how the array allocates space for the snapshot.

•Demand allocated—The array allocates only enough space to store metadata and pointers to the source data. As the source is overwritten, the array allocates more space and copies the original data to the snapshot. Use demand-allocated snapshots when less than 10–25% of the capacity of the source will change over the life of the snapshot.

•Fully allocated—The array allocates only enough space to store metadata and pointers to the source data, but reserves space equal to the capacity of the source virtual disk. As the source is overwritten, the array allocates more space and copies the original data to the snapshot.

Use fully-allocated snapshots when more than 25% of the capacity of the source will change over the life of the snapshot.

Snapshot guidelines

Follow these guidelines for using snapshots:

•The array must have a local replication license.

•The maximum number of snapshots per source varies based on the array controller software version. For specifics, see the HP P6000 Enterprise Virtual Array Compatibility Reference.

•A snapshot must be created in the same disk group as the source virtual disk.

•The redundancy (Vraid) level of a snapshot must be the same as, or lower than, the source.

•All snapshots of the same virtual disk must be the same type (demand allocated or fully allocated) and redundancy (Vraid) level.

•If the disk group has insufficient space for demand-allocated snapshots, the snapshots will automatically be invalidated, but the source virtual disks will continue accepting requests.

•Snapshots are included in the maximum number of virtual disks per array.

Snapshots cannot be created when the disk to be replicated is:

•A snapshot

•A disk that is the source of a mirrorclone (however, snapshots from a mirrorclone are possible)

•In the process of normalizing (snapclone in progress) or being deleted (P6000 Command View 10000000 or earlier)

•See also, “Optimizing snap creation” (page 40).

Monitoring snapshot space

Demand-allocated snapshots must be able to grow as the source or snapshot is modified, otherwise all snapshots in the disk group become inoperative. As demand-allocated snapshots grow, the

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Contents HP P6000 Command View User Guide AbstractSee Internet Protocol support Contents Configuring HP P6000 Command View advanced tasks Troubleshooting HP P6000 Command ViewMaintaining and managing HP P6000/EVA storage systems Monitoring storage system eventsComponents Support and other resources HP array event code formats and descriptionsGlossary 100 Index 103 HP P6000 Command View software suite OverviewPrerequisites HP P6000 Command View features Server-based and array-based managementServer-based configuration Array-based configuration HP Management Integration FrameworkUser interface Storage systems point of view Hardware-SeeHardwareSettings point of view Settings point of viewAccessing HP P6000 Command View Browsing to server-based HP P6000 Command ViewRunning server-based HP P6000 Command View from the desktop Browsing to array-based HP P6000 Command ViewInternet Protocol support IP address formatsManaging security and passwords Server-based HP P6000 Command View security groupsArray-based HP P6000 Command View security groups Password protection for storage systemsEnabling management of a password-protected storage system Password formatsConsiderations Disabling management of a password-protected storage system Setting a password for HP EVA storage systemsDisabling management of a password-protected storage system Single sign-on from HP Systems Insight ManagerManaging security and passwords Licensing HP P6000/EVA storage systems Licenses to use and license keysLicense types Instant-on licensesModel upgrade licensing Model upgrade supportData migration licenses Fcip licensesConfiguring email to receive LTUs Activating an instant-on licenseRetrieving licenses Entering license keysImporting licenses Validating the licenseAdding an LTU Deleting incorrectly entered license keys Displaying temporary license expiration dateProvisioning storage Disk groupsWorking with disk groups Disk types Disk group typesGeneral guidelines Disk group occupancy and occupancy alarm level Disk group capacityNumber of physical disks in a group Redundancy Vraid levels Working with virtual disks in HP P6000 Command View Virtual disksVirtual disks Working with hosts in HP P6000 Command View HostsPresentation Online virtual disk migrationMirrorclone migration Thin provisioningThin provisioned disk Replicating storage HP P6000 Business Copy softwareSnapclones Snapshots Snapshot typesSnapshot guidelines Monitoring snapshot spaceMirrorclones Mirrorclone guidelinesSynchronized mirrorclone guidelines Fractured mirrorclone guidelinesContainers Mirrorclone statesUsing containers preallocation Optimizing replication performancePlanning for host I/O workloads Optimizing snap creationMinimizing snapclone workloads Minimizing the number of snapshotsMinimizing simultaneous replication operations HP P6000 Continuous Access software Working with DR groups in HP P6000 Command ViewDR groups Creating DR groups Data replication protocol optionsReplicating storage Maintaining and managing HP P6000/EVA storage systems Initializing storage systemsUser-initiated service mode USER-INITIATED Service Mode Active on this Storage SystemUninitializing storage systems Starting the storage systemShutting down the storage system HSV210A controller rear view Working with hardware in HP P6000 Command View HardwareRemote service test Verifying hardware statusStorage system identity information Using multiple management servers to manage arrays Updating HP controller softwareConfiguring iSCSI devices Monitoring storage system events Events overviewEmail notification Management server event logViewing events Controller termination event logConfiguring event notification Configuring host notificationViewing additional information Filtering events by severity Applying a customized host notification listApplying a customized event configuration file Retrieving the parse fileSelecting individual events Retrieving the Management Information Base Sending the event file Configuring HP P6000 Command View advanced tasks Setting user interface optionsCreating page footer messages Setting audit logging options Setting a remote location for audit logsChanging port and timeout parameters Changing the login credentials array-based managementRunning HP P6000 Command View in a multi-homed environment Https//managementmoduleIPaddress2373Troubleshooting HP P6000 Command View Restarting the HP P6000 Command View serviceUsing the right-click menu Optimizing performanceNavigation pane lists duplicate arrays Error messages in the user interface Failed communication link to iSCSI devicesFailed connection warning for empty controller host ports Failed entities reported on the disk enclosureTroubleshooting access to array-based HP P6000 Command View Failed blower power supplyFailed transceiver Failed I/O moduleUnexpected behavior when using older Windows HBA driver Storage system connection down error messageVirtual disk sizes displayed incorrectly IPFilter page incorrectly displays IPv6 addressVersion numbers differ Webes 5.5 receiving events inconsistentlyComponents \Program Files\Hewlett-Packard\EVA Performance MonitorDisplaying historical state changes and performance data HP P6000 Performance Data Collector valid objecttype valuesConfiguring the HP P6000 Command View server HP P6000 Performance Data Collector objectid valuesConfiguration file for performance and state data logging Displaying HP P6000 Command View access credentialsConfiguring HP P6000 Performance Data Collector Logging configuration fileEvents and logs Configuration recommendations Connecting to HP P6000 Performance Data Collector remotelyProhibited commands SSL protocolUsing friendly names Backward compatibilityCreating the friendly names host file Adding friendly namesMapping worldwide names to friendly names Adding friendly names manuallyUsing short names Using the command line interface Viewing arraysSpecifying the output Refreshing dataFiltering data Specifying data output in multiple filesCommands HP P6000 Performance Data Collector commandsLuns Command modifiers HP P6000 Performance Data Collector command modifiersUsing the graphical user interface NotsPage Configure filtering Data filteringObjects and counters HP EVA storage array HP EVA storage controllerHP EVA virtual disk HP EVA virtual disk group HP EVA host connection HP EVA host port statisticsHP EVA physical disk HP EVA physical disk groupHP EVA DR tunnels HP EVA DR Group Information Support and other resources Contacting HPRelated information Typographical conventions WebsitesDocument conventions HP array event code formats and descriptions Event code formatEvent code types and descriptions Software component IDsCorrective action codes Event information packet EIP typesHP array event information packet EIP types Coupled crash control codes HP array coupled crash control codesDump/restart control codes HP array dump/restart control codesGlossary EVASAN See also virtual disk Index CLIIndex 105
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