HP XP7 Fast Snap User Guide (TK913-96003)

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

• “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