HP 3PAR Cluster Extension Software Administrator Guide (5697-1429, March 2012)

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).
Pre-execution and post-execution programs
HP 3PAR Cluster Extension can invoke pre-execution and post-execution programs prior to or after
a HP 3PAR Cluster Extension failover/failback function. These programs can be any executable,
and must be able to provide return codes to HP 3PAR Cluster Extension. If the programs add
significant execution time to the application service startup process, the timeout values for the
startup process must be adjusted in the cluster software.
HP 3PAR Cluster Extension transfers information as CLI arguments to the pre-execution and
post-execution programs. You must not specify CLI arguments. Pre-executables and post-executables
must be specified by full path in the PreExecScript and PostExecScript objects. If no executable is
specified (there is an empty value for the object), no preprocessing or postprocessing is performed.
If the object is not defined, then the argument value is empty.
The following arguments are transferred to the scripts in this order:
1. Resource name
2. DC A HP 3PAR storage system serial number
3. DC B HP 3PAR storage system serial number
4. DC A Remote Copy volume group
5. DC B Remote Copy volume group
6. DC A host (server) names
Pre-execution and post-execution programs 71