HP XP Racks - Manual (Page 53)

Related topics
•
“Splitting BC pairs” (page 45) .
Reverse resynchronization
You can use one of the following methods to restore pairs, including the requirements and
restrictions:
•
Reverse Copy (Secondary > Primary). A full restoration from the S-VOL to the P-VOL. The
differential data is updated to the P-VOL.
During a Reverse Copy you can delete or suspend the pairs, but you cannot create, split, or
resynchronize pairs that share the same P-VOL. The P-VOL is inaccessible to hosts.
If you are sharing a Cnt Ac-S or Cnt Ac-J volume with an BC volume, you cannot create a Cnt
Ac-S or Cnt Ac-J pair with the shared volume.
You cannot use Reverse Copy the following pairs:
◦ An BC/SS L2 pair.
◦ (If you are sharing the P-VOL with an FC Z/FCSE volume) The BC Z pair.
•
Quick Restore (Secondary > Primary). A partial restoration that does not copy the data but
does the following:
◦ Swaps the P-VOL and S-VOLs including their RAID levels, HDD types, and Cache Residency
settings.
◦ Pairs the volumes (“PAIR” status).
◦ Exchanges the P-VOL and S-VOL encryption statuses if an BC pair consists of encrypted
volumes and a non-encrypted volume.
CAUTION: To prevent the two volumes from being swapped, the P-VOL and S-VOLs must
have the same CLPR numbers.
During a Quick Restore, the P-VOL and S-VOL are inaccessible. After a Quick Restore, the
P-VOL is accessible.
Best Practice: If you have a small amount of differential data, use Reverse Copy instead of
Quick Restore, since Reverse Copy completes faster.
If you use volumes for which you set Data Retention access attributes, Quick Restore does not
exchange the P-VOL and S-VOL access attributes.
For more information about using volumes for which you set Data Retention access attributes,
see
“Sharing volumes and Data Retention access attributes” (page 23) .
NOTE: The RWC can show outdated information after a Quick Restore. To show the latest
information, click Refresh View.
NOTE: To minimize the time it takes to Quick Restore an BC pair, do not perform LDEV
maintenance while the Quick Restore is processing.
For more information about performing LDEV maintenance, see HP XP7 Provisioning for Open
Systems User Guide.
You can delete or suspend the pair while you are restoring the pair using Quick Restore but
you cannot do the following:
◦ Create, split, or resynchronize pairs that share the same P-VOL.
◦ Create a Cnt Ac-S or Cnt Ac-J pair with a volume shared by BC.
BC pair resynchronization 53