Administrator's Guide

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