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

1 XP Cluster Extension features
HP StorageWorks XP Cluster Extension Software monitors HP StorageWorks XP Continuous Access
Software disk pairs and enables automatic access to remote data copies when clustered applications
become unavailable locally. XP Cluster Extension integrates with popular cluster software to ensure
that consistent and concurrent data copies on HP disk arrays can be accessed when needed.
Integration into cluster software
XP Cluster Extension integrates with the following cluster software products:
• High Availability Cluster Multi-Processing (HACMP)
• Microsoft Cluster Service (MSCS)
• VERITAS Cluster Server (VCS)
• SUSE Linux Enterprise High Availability Extension (SLE HA)
• Red Hat Cluster Suite (RHCS)
Integrating XP Cluster Extension with cluster software allows you to manage a disk array as if it were
a disk or volume group of the clustered application.
For supported cluster software versions, see the HP SPOCK website: http://www.hp.com/storage/
spock.
Enhanced disaster tolerance
HP XP Continuous Access Software copies valuable data to a remote data center so that you can
restore application service after a local server, storage, or data center failure. Disk arrays with XP
Continuous Access Software can change mirroring direction, swapping the primary/secondary
relationship of disk pairs almost instantaneously if the application must access the secondary disk.
This feature ensures that the failback process is as fast as the failover process. If the links between
your primary and secondary disk arrays are broken, each array maintains a bitmap table to
synchronize the changes when the links become available again.
Because cluster software requires the application service to have read/write access to data disks and
because the secondary volume of an XP Continuous Access Software disk pair is normally read-only,
the failover process using cluster software alone typically involves manual intervention. With XP Cluster
Extension Software, manual intervention is required only if the current disk array states and user
settings conflict with the rules stored in the XP Cluster Extension database.
Automated monitoring and redirecting of XP Continuous Access
Software pairs
XP Cluster Extension monitors the health of the XP Continuous Access Software links between your
arrays. When it detects a lost and later re-established link, it automatically resynchronizes the suspended
disk pairs, ensuring that the most current data is available on either site. For information on configuring
resynchronization parameters, see “Monitoring and resynchronizing device groups” on page 143.
XP Cluster Extension Software Administrator Guide 11