HP 3PAR Cluster Extension Software Administrator Guide for Windows (5697-1821, April 2012)

NOTE: Host persona setting varies based on the Windows operating system installed on the
cluster nodes, For more information, see the HP 3PAR Implementation Guide.
no_fail_wrt_on_err settings
The no_fail_wrt_on_err policy apply only to synchronous Remote Copy.
The no_fail_wrt_on_err group policy (default policy) allows writes to a primary Remote Copy
volume group even though the link between the systems in the Remote Copy pair is broken.
Continuing to write changes despite a broken link leads to a loss of synchronization between
primary and secondary Remote Copy volume groups. The no_fail_wrt_on_err policy is used
when you would rather keep the applications that are writing the data running, even when the
Remote Copy has failed and become out of sync. After the error that caused the broken link is
resolved, you must manually restart the Remote Copy operation between the members of the Remote
Copy pair to bring the Remote Copy in sync again.
NOTE: HP 3PAR Cluster Extension supports only the Remote Copy volume groups with
no_fail_wrt_on_err policy. For information on setting the Remote Copy volume group policies,
see the “Remote Copy Commands” section in HP 3PAR Remote Copy User’s Guide .
Remote Copy and 3PAR Virtual Domains
Remote Copy checks HP 3PAR Virtual Domains (domains) on the remote system to ensure that the
virtual volume is mirrored to the same domain name as the local domain name. The domain needs
to be called a correct domain name. For more information on domains, see the HP 3PAR Concepts
Guide and for instructions on setting up domains, see the HP 3PAR CLI Administrator’s Manual.
NOTE: When configuring the HP 3PAR storage system password file for Cluster Extension usage,
user in the password file should have access to all the domains of Remote Copy virtual volumes
managed by Cluster Extension.
Promote issue
Data copy between the primary and the secondary Remote Copy volume groups may fail due to
many reasons (like RC link goes down abruptly or RC link is stopped manually or RC Volume group
is stopped manually). During this time, Remote Copy volume groups go to the stopped state. Before
the data copy operation begins, the HP 3PAR Inform OS will take the point in time snapshot of the
secondary volumes. When the data copy between the primary and the secondary RC volumes
group fails, the point in time snapshots at the seconday site will be promoted to the base volume
by the Remote Copy feature of HP 3PAR Inform OS. When the promote operation is in progress,
HP 3PAR CLI commands like startrcopygroup and setrcopygroup reverse or failover
or restore are issued for the volume group by CLX during the online operation. Sometimes these
CLI commands may fail resulting in CLX online operation to fail. At this time, when the server cluster
retries the online operation on one of the cluster nodes for the HP 3PAR CLX resource, if the HP
3PAR CLI commands issued by CLX succeed, then CLX resource also comes online successfully. In
this way, user can recover from this situation. Otherwise if the cluster resource is not configured
for retry operation, CLX resource has to be brought online manually through the server cluster GUI
or Cluster CLI. If clx3parrun utility is used to perform the failover operations in the above scenario,
then this utility has to be run multiple times till the CLX resource comes online successfully.
Failure of starting Remote Copy volume groups during CLX online operation
If the local replication role is secondary, the remote replication role is primary, and the remote
copy link is up, CLX executes stop, reverse (setrcopygroup stopgroup reverse), and start
operations (startrcopygroup) for the Remote Copy volume group. If the stop and reverse
operations succeed, then the secondary volumes become read-write and Cluster Extension resource
comes online even though the start operation may fail. If the start operation fails (may be due to
no_fail_wrt_on_err settings 85