HP XP7 Storage - Manual (Page 83)

Fast Snap pair resynchronization
Resynchronizing a pair updates the S-VOL with the differential data and deletes the replaced data,
the data in the pool. Resynchronizing a pair maintains the relationship between the P-VOL and
S-VOLs.
CAUTION: The amount of time that is required to resychronize depends on the following:
•
The amount of capacity the pool is using.
•
The amount of pairs being resynchronized concurrently.
Related topics
•
“Pair resynchronization methods” (page 83)
•
“Resynchronizing Fast Snap pairs” (page 83)
Pair resynchronization methods
You can forward or reverse resynchronize pairs. A forward resynchronization resynchronizes the
S-VOL from the P-VOL. A reverse resynchronization restores the P-VOL from the S-VOL.
Related topics
•
“Forward resynchronization” (page 83) .
•
“Reverse resynchronization” (page 83) .
Forward resynchronization
The following is a list of the methods you can use to forward resynchronize pairs, including the
requirements and restrictions:
•
Normal Copy (Primary > Secondary. A full forward resynchronization of data from the P-VOL
to the S-VOL. The differential data is copied to the S-VOL.
•
Quick Resync (Primary > Secondary). The FS pairs are forward resynchronized (“PAIR” status).
During the Update Copy operation, the differential data is copied to the S-VOL.
Reverse resynchronization
The following is a list of the methods you can use to restore pairs, including the requirements and
restrictions:
•
Reverse Copy (Secondary > Primary). A full restoration of P-VOL data from the S-VOL.
•
Quick Restore (Secondary > Primary). A partial restoration that copies only the S-VOL differential
data to the P-VOL.
Resynchronizing Fast Snap pairs
You can resynchronize pairs that you have split or that the storage system has suspended.
Resynchronizing FS pairs does the following:
•
Updates the S-VOL so that it is again paired with the P-VOL.
•
Deletes the P-VOL’s snapshot data, which decreases the pool usage rate and increases the
unused capacity.
Fast Snap pair resynchronization 83