HP StoreVirtual 4000 User Manual page 35

Failover to the backup application server
To maintain availability of the applications and the remaining data, the following process occurs:
1. A script or other application monitoring the production application server discovers that the
primary volume is not available. A script executes to fail over to the backup application server.
2. The backup application server executes a script to convert the remote volume into a primary
volume so that the volume can be accessed by the backup application server. For information
about scripting, see the HP LeftHand Storage Command Line Interface User Guide and the
sample scripts available at http://www.hp.com/go/P4000downloads.
3. Because the backup application server was configured to access the remote (now primary)
volume, operation of the backup application server begins.
The application continues to operate after the failover to the backup application server.
Failback to the production configuration
When the production server and volumes become available again, you have the following two
failback options:
Resume operations using the original production server, and then return the backup volumes
to their original remote status, as illustrated in
of data that was written to the backup volumes since the failure back onto the production
volumes.
Continue operating on the backup application server. When the production server and volumes
become available, configure the production server to be the backup server (role reversal).
Merging data for failback
In the failover scenarios described above, there are probably two snapshots with different data.
As part of failback, users must make a decision whether to merge the data from the two snapshots
and the most effective method for doing so. For more information see
between the acting primary volume and the original primary volume" (page
Figure 10 High availability configuration during failback
Figure 10 (page 35). This requires migration
"Synchronizing the data
Using Remote Copy for business continuance
29).
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