Disaster Recovery For Multiple Primary And Secondary Storage Systems; Consistency Of Data Update Sequence When A Disaster Occurs; Recovery Procedures With Shared Volumes - HP XP P9500 User Manual

The following procedure explains how to resume normal operations at the primary site by using
Business Continuity Manager.
1. At both Continuous Access Journal Z sites, make sure that the Continuous Access Journal Z
components are operational and free of failures.
2. Make sure that the pair status of P-VOLs and S-VOLs in all Continuous Access Journal Z pairs
is Duplex.
3. Stop the applications at the secondary site.
4. Execute the Business Continuity Manager command YKSUSPND with the FLUSH S-VOL and
PERMIT parameters to the copy group. If an error occurs, correct the error source and return
to step 1 after resuming business tasks at the secondary site.
5. If no errors occur, wait until suspension finishes. After suspension finishes, check whether there
is an S-VOL on the local site whose status is other than Suspend. If such a pair exists, remove
the error cause and go back to step 1 after resuming your business task at the secondary site.
6. When all S-VOLs at the primary site are in Suspend status, data in P-VOLs and S-VOLs are
the same. S-VOLs at the primary site are ready for host read/write activity. Resume applications
at the primary site.
7. Execute the YKSUSPND FORWARD command on the copy group. YKSUSPND is a Business
Continuity Manager command and FORWARD is an option. Wait until suspension completes.
The pairs will be in the SWAPPING state.
8. After suspension completes, execute the Business Continuity Manager YKRESYNC FORWARD
command on the copy group. This reverses P-VOLs and S-VOLs to resynchronize pairs and
restores copy direction to its original direction.

Disaster recovery for multiple primary and secondary storage systems

Consistency of data update sequence when a disaster occurs

When a failure occurs in some primary or secondary storage system, all journals in the extended
consistency group are suspended and remote copy operations are suspended. The consistency of
data update sequence is maintained if a failure occurs in a primary storage system, but the
consistency is not maintained if a failure occurs in a secondary storage system.
Disaster recovery for multiple primary and secondary storage systems
The following is an example of the procedure that should be followed when a disaster or failure
occurs in the primary site in multiprimary and multisecondary storage systems configuration:
1. Switch operations from the primary site to the secondary site.
2. Reverse the copy direction, so that data are copied from the secondary site to the primary
site.
3. After recovery of the primary host or storage system finishes, switch operations from the
secondary site to the primary site.
This disaster recovery procedure is the same as when only one primary storage system and only
one secondary storage system is used.

Recovery procedures with shared volumes

Restoring operations with shared Continuous Access Journal Z and Continuous Access Synchronous
Z or Business Copy Z volumes is a bit more complicated than with a straight Continuous Access
Journal Z pair. The following sections provide various procedural guidelines. They are intended
to offer guidance not only for immediate recovery from disaster or failure, but also for moving
forward toward reconfiguring the system.
"Recovery in a 3DC cascade configuration " (page 106)
"Recovering from primary site disaster in 3DC multi target configuration" (page 107)
Disaster recovery for multiple primary and secondary storage systems 105