HP XP P9500 Storage - Manual (Page 21)

Requirements, restrictions, and recommendations for shared volumes
The following is a list of the requirements, restrictions, and recommendations for using the At-Time
Split with shared Cnt Ac-S Z or Cnt Ac-J Z volumes:
•
BCM is required.
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You must share the BC Z P-VOLs with the Cnt Ac-J Z or Cnt Ac-S Z S-VOLs.
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The BC Z pairs must be registered in the same BC Z consistency group to ensure consistent
backup operations.
•
If you are sharing BC Z P-VOLs in a storage system with Cnt Ac-J Z or Cnt Ac-S Z S-VOLs, to
prevent the At-Time Split from ending abnormally, ensure the status of all Cnt Ac-J Z or Cnt
Ac-S Z pairs in the consistency group is the same, DUPLEX or Split/SUSPOP.
•
You can perform one split operation per BC Z consistency group.
•
The specified split time remains enabled even after the split operation on BC Z pairs is
completed. Therefore, delete the registered split time before specifying a new split time.
•
You can reset the specified split time by running PS OFF of RCU.
•
If you use the At-Time Split when Cnt Ac-J Z and Cnt Ac-S Z volumes are in the following
configurations, enable the time stamp transferring option of all the Cnt Ac-S Z pairs in the
journal to insure data consistency in the BC Z consistency group:
◦ 3DC Cascade configuration
◦ 3DC multi-target configuration that has been switched to a cascade configuration during
disaster recovery
•
You cannot add pairs, resume pairs, or suspend pairs from BCM when a split time is set for
a BC Z consistency group, unless you first delete the split time.
•
Cnt Ac-J Z pairs must belong to the same journal group. If multiple journal groups are registered
in one BC Z consistency group, consistent backup cannot be ensured on BC Z S-VOLs.
•
With Cnt Ac-J Z, if a pair is suspended due to a failure, Cnt Ac-J Z journal data created before
the split time may not be restored to the Cnt Ac-J Z/BC Z volume after the split operation is
completed. This is because the split time and the actual starting time of the operation are not
necessarily the same in this circumstance. The starting time delays according to the amount
of journal data in the journal volume at the split time. For example, if the journal volume
contains data that needs one hour to be restored, the starting time of the split operation delays
for an hour.
•
With Cnt Ac-J Z, three split operations can be performed per Cnt Ac-J Z journal (equivalent
to three BC Z consistency groups).
•
With Cnt Ac-J Z, you can select the Quick Split or Steady Split for the BC Z At-Time Split
operation.
•
With Cnt Ac-J Z, if you specify a split time, you cannot restore the Cnt Ac-J Z pair.
To run the Reverse Resync, delete the split times of the BC Z pair whose S-VOL is related to
the restore journal.
For more information about the Reverse Resync, see the HP XP P9000 RAID Manager User
Guide and Business Continuity Manager User Guide.
•
With Cnt Ac-J Z, if a restore journal has a timeout period that ends after the split time, journal
data may not be detected. In this case, the BC Z split operation runs after the timeout period.
You set the timeout value according to your requirements. The default value is 6 hours.
At-Time Split at a specific time 21