HP StorageWorks XP Cluster Extension Software Administrator Guide (T1656-96035, April 2010)

9 Advanced XP Cluster Extension
configuration
This chapter describes advanced XP Cluster Extension configuration procedures.
Implementing rolling disaster protection
To implement rolling disaster protection, create XP Business Copy Software disk pairs for the local XP
Continuous Access Software disks.
• Create the XP Business Copy Software disk pairs using the –m noread option of the paircreate
command. This option ensures that XP Business Copy Software disks are unavailable to other
services and reserved for rolling disaster protection only.
• Map the XP Business Copy Software S-VOLs to a backup server, not to the local cluster node.
When XP Cluster Extension suspends the XP Business Copy Software pairs, they become available
to the local server, which could result in duplicated volumes, disk group IDs, or signatures.
CAUTION:
You must ensure that at least one XP Business Copy Software disk pair is in PAIR state. If rolling
disaster protection is enabled and none of the XP Continuous Access Software mirrored disk pairs
have an XP Business Copy Software disk pair that is in PAIR state, XP Cluster Extension returns a
global error, and you will not be able to activate the application service.
You can use forceflag to start the application service. See “Enabling write access regardless of
disk pair state” on page 144. In this case, XP Cluster Extension disables rolling disaster protection.
Using XP RAID Manager with rolling disaster protection
Rolling disaster protection does not require that you define XP Business Copy Software disk pairs in
the XP RAID Manager horcmX.conf files. XP Cluster Extension uses the MU number to monitor and
control associated XP Business Copy Software pairs. You must create an XP RAID Manager
configuration file to control the XP Business Copy Software disk pairs that are outside XP Cluster
Extension control.
XP Cluster Extension Software cannot suspend XP Business Copy Software disk pairs on the remote
XP disk array in the remote data center if the XP RAID Manager instance in the remote data center is
not running or not reachable.
Setting XP Cluster Extension objects to enable rolling disaster protection
To enable rolling disaster protection with XP Business Copy Software, set the BCEnabledA and
BCEnabledB objects for data centers A and B. When these objects are set to YES, rolling disaster
protection is enabled and XP Cluster Extension checks whether the configured XP Business Copy
Software disk pairs are in PAIR state. Before initiating the resynchronization operation, XP Cluster
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