HP XP P9500 Storage - Manual (Page 109)

4. Select the pairs that you want to suspend (or the volumes whose pairs you want to suspend),
right-click the selected pairs to display the menu, and select the Pairsplit-E command to open
the Pairsplit-E dialog box.
5. On the Pairsplit-E dialog box, select the pairs you want to suspend, and click OK to reflect
the settings to the Preview List on the Pair Operation window.
To remove pairs from the list, select the unneeded pairs, right-click while selecting the pairs,
and then select the Delete command from the menu that displays by right-clicking.
6. Repeat steps 4 and 5 to suspend additional pairs in the Pair Operation window.
7. In the Pair Operation window, click Apply to suspend the specified pairs.
The Pair Operation window displays the results of the Pairsplit-E operations (i.e., pair status
changed to PSUE).
Resynchronizing pairs
You resynchronize a pair that was split by a user or suspended by the storage system.
Resynchronizing updates the S-VOL so that it is again paired with the P-VOL.
CAUTION: Resynchronizing the pair does not guarantee that P-VOL data is the same as S-VOL
data. Data in the two volumes is the same only when the pair is split.
•
You can forward resync—from P-VOL to S-VOL, and reverse resync—from S-VOL to P-VOL.
You can perform a Normal Copy or a Quick Resync, in both directions. ◦
◦ The P-VOL remains accessible to hosts for both read and write operations during a Normal
Copy operation. The S-VOL becomes inaccessible to hosts during a Normal Copy
operation.
◦ The P-VOL remains read-disabled during the Reverse Copy operation.
•
In a forward Quick Resync from P-VOL to S-VOL, status changes to PAIR without actually
resynchronizing the data in the S-VOL. Differential data is copied to the S-VOL when update
copy operations are performed.
◦ The P-VOL remains accessible to all hosts for both read and write operations during a
quick resync operation.
◦ In a forward Quick Resync you cannot be sure the data in the P-VOL and S-VOL is the
same when there is no host I/O during the operation. You must split the pair to ensure
that data is the same.
•
In a Quick Restore (reverse Quick Resync), the P-VOL and S-VOL are swapped. No actual
data is copied, and the pair is placed in PAIR status.
◦ The P-VOL and S-VOL are inaccessible during this operation. When the operation
completes, the P-VOL becomes accessible.
◦ When differential data between P-VOL and S-VOL is small, the Reverse Copy operation
may be completed faster than the Quick Restore operation.
•
Performing LDEV maintenance work during the Quick Restore process increases the time for
the operation to complete.
NOTE: You can use PPRC to perform a Normal Resync operation on all pairs in a consistency
group. To perform the Quick Resync, Reverse Copy, or Quick Restore with PPRC, you must run the
desired command on one pair at a time.
Resynchronizing pairs 109