HP 3PAR storage system and the settings in the UCF.cfg file, you must evaluate the following considerations:

•HP 3PAR Cluster Extension uses HP 3PAR Command Line Interface (CLI) to communicate with the HP 3PAR storage system, depending on the settings of HP 3PAR command timeout property, and the number of Remote Copy volume groups managed by HP 3PAR storage systems, the online operation could time out. This can also happen if clx3PARrun is used in a script or called by another program or 3PAR storage system IP cannot be reached.

•In the UCF.cfg file, if the ApplicationStartup attribute is set to RESYNCWAIT, HP 3PAR Cluster Extension tries to resynchronize virtual volumes and waits until the Remote Copy volume group is in a synced state. Depending on the amount of data to be transferred, it could take hours to resynchronize. If this is the case, clx3PARrun may take some time to return. Do not stop clx3PARrun, use the HP 3PAR Management Console GUI or CLI to check the progress of syncing.

•Depending on the amount of data that is out of sync between the source and destination virtual volumes while the Remote Copy link(s) is unavailable, a resynchronization or a complete copy operation is initiated when the Remote Copy link(s) is re-established. The amount of delta data to be transferred between the source and destination virtual volume could be large enough for the copy process to take some time.

•To prevent the failover timeout trigger from terminating a failover command before it is finished, the time to copy an average amount of daily processed (write) data should be measured and the resource online timeout interval should be adjusted accordingly. Use only one (the slowest) link used for Remote Copy to measure the copy time. This ensures that the average daily generated data can be transferred fast enough from the remote HP 3PAR storage system, even in the event of a single surviving replication link between the HP 3PAR storage systems. In general, because the failover environment is dispersed into two (or more) data centers, the failover time cannot be expected to be the same as it would be in a single data center with a single shared disk device.

Restrictions for customized implementations

The following restrictions apply when using the HP 3PAR Cluster Extension CLI:

•The HP 3PAR Cluster Extension CLI command clx3PARrun must be invoked before the associated disk resources are activated on a server.

•Associated disk resources must not be activated on any other system. If other disk resources are activated, HP 3PAR Cluster Extension may remove write-access rights for those disk devices (putting them in read-only mode).

Cluster Extension Cmdlets for CSV and Virtual Machine Management

The following PowerShell Cmdlets are supported by CLX to perform various operations:

•Add-CSVDependencyOnCLX3PAR

•Add-VMDependencyOnCLX3PAR

•Get-VMOnClusterSharedVolumeListForCLX3PAR

As part of the CLX installation, these Cmdlets are registered on every node of the cluster. Before invoking any of these Cmdlets, user needs to load the snap-in in every PowerShell session. To load the Snap-In, CLX has provided a PowerShell script file AddClx3PARCmdletsSnapIn.ps1 which exists at the location <CLX Install Directory>\bin.

User needs to run this script that will load the PowerShell Snap-In. Once the Snap-In is loaded, user can run the supported Cmdlets to perform the various required operations. These Cmdlets are available till the PowerShell session exists. Once the session is closed, the Snap-In will get unloaded and these Cmdlets will not available to the user.

58 CLI commands and utilities