User's Manual

12 Special notes
• If a single virtual machine sits on two datastores and two virtual volumes, it is recommended
to include both virtual volumes in the same Remote Copy group.
• In a disaster recovery scenario, when Remote Copy links are down, the Remote Copy group
status could still be Started. A failover attempt will not be successful until the Remote Group
status becomes Stopped.
• HP 3PAR SRA configuration will not be deleted in the Windows registry when the HP 3PAR
SRA package is uninstalled.
• If a virtual machine sits on a spanned datastore, all virtual volumes used for the spanned
datastore need to be included in a single Remote Copy group.
• SRM might potentially time out if multiple test failover or recovery operations are run
simultaneously. Rerun the operation if the time out error occurs. Alternatively, the time out error
might be avoided if the operations are run sequentially.
• If an ESX(i) host has both FC and iSCSI definitions created on the HP 3PAR storage system
and vCenter Server also has both FC and iSCSI software adapter configured, per the vCenter
Server's request, LUNs will be exposed to both host definitions in the event of failover. However,
if only one host definition is presented on the HP 3PAR storage system (either FC or iSCSI),
HP 3PAR SRA will only expose LUNs to whichever is defined on the HP 3PAR Storage system.
• It is strongly recommended to configure one protected group per Remote Copy group.
• If multiple Remote Copy groups are included in one protected group, it is recommended to
set the same sync time on all of the periodic Remote Copy groups.
• Remote Copy group reserves .r for naming. Do not include the reserved naming in your
Remote Copy group name.
• SRM_RO_<VVID>, SRM_RW_<VVID>, SRM_RECOVER_RO_<VVID>, and
SRM_TARGETBK_RO_<VVID> are reserved virtual volume naming convention for HP 3PAR
SRA.
• SRM might potentially run into a virtual volume promote operation during re-protect. If this
occurs, retry the re-protect operation.
• Devices on the protected storage system should be read-only after prepareFailover and
optionally take snapshots of the source devices for restoration if needed. The way to make a
device read-only to meet SRM's specification before failover is to remove VLUN exposure so
that no one has access to it. Remote Copy will internally manage the snapshot taking in case
something goes wrong during the failover process. In addition, HP 3PAR SRA will also take
a snapshot of the devices on the protected site of the SRM (Remote Copy role Primary or
Primary-Rev) for restore purposes since the user might activate the Remote Copy sync after
failback (setrcopygroup restore) which would destroy the data content. The snapshot
name will have the following prefix: SRM_RECOVER_RO_<VVID>.
• Devices on the protected storage system should be read-only after failover. This is the same
with prepareFailover. The only difference is if the failover is part of the failback workflow,
the protected storage system will become secondary after failback using the setrcopygroup
restore command. Devices under the secondary Remote Copy group will automatically
have read-only access.
• Devices on the recovery storage system should be read-writable after failover. The way to
make the recovery storage system devices read-writable is to make the Remote Copy role on
the recovery storage system to Primary or Primary-Rev with the setrcopygroup
failover/restore or setrcopygroup reverse command.
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