HP StorageWorks P9000 Cluster Extension Software Administrator Guide (TB534-96009, February 2011)

1 P9000 Cluster Extension features
HP StorageWorks P9000 Cluster Extension Software monitors P9000 and XP Continuous Access
disk pairs and enables automatic access to remote data copies when clustered applications become
unavailable locally. P9000 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
P9000 Cluster Extension integrates with the following cluster software products:
• Microsoft Cluster Service (MSCS)
• SUSE Linux Enterprise High Availability Extension (SLE HA)
• Red Hat Cluster Suite (RHCS)
Integrating P9000 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
The 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
Continuous Access 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 a Continuous Access disk pair is normally read-only, the
failover process using cluster software alone typically involves manual intervention. With P9000
Cluster Extension Software, manual intervention is required only if the current disk array states and
user settings conflict with the rules stored in the P9000 Cluster Extension database.
Automated monitoring and redirecting of Continuous Access pairs
P9000 Cluster Extension monitors the health of the Continuous Access 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/copy
groups” (page 95).
Rolling disaster protection
A rolling disaster is a catastrophic event that affects the remote site after an outage at the local
site. In a rolling disaster, data stored on remote disks can be entirely lost during a recovery attempt.
To ensure the survival of critical data during a resynchronization/restore operation, P9000 and
XP Business Copy pairs can be associated with the local data disks. P9000 Cluster Extension
recovers automatically, provided that a local Business Copy mirror can be suspended.
Although the local copy can be out of date, it represents the best starting point for the recovery.
P9000 Cluster Extension also resumes local Business Copy mirrors automatically, if specified, to
allow the local site to keep an up-to-date image of the primary data. To implement rolling disaster
protection, see “Implementing rolling disaster protection” (page 93).
8 P9000 Cluster Extension features