You can reverse a FlashCopy relationship that has change recording enabled and
restore the tracks from the target volume to the source volume. However, the
background copy process of the original FlashCopy must complete before you can
reverse the order of the FlashCopy relationship to its original source and target
relationship.
With the fast reverse restore feature, you can reverse a FlashCopy relationship that
has change recording enabled without waiting for the background copy of the
original FlashCopy to complete. It is not required that you use the fast reverse
restore feature during disaster recovery operations; however, the time to recover
could be significantly longer if you do not.
Recovering from a disaster using the fast reverse process
Use this process for the Global Mirror fast reverse restore feature, which allows a
FlashCopy relationship to be reversed without waiting for the background copy of
the original FlashCopy to complete.
You can use the fast reverse restore feature of FlashCopy to speed up the recovery
process. Using the DS Storage Manager, you make the following selections:
1. Create a FlashCopy target on the existing Metro Mirror source by choosing the
FlashCopy target and a source Metro Mirror .
2. Select the Fast Reverse restore option.
FlashCopy copies the partial data that had been copied to Volume C before the
disaster occurred to Volume B. This creates a consistent copy on Volume B.
Processing also provides a background copy of the consistent group for Volume
B.
Note: When you initiate the fast reverse restore process, Volume C becomes
unusable.
Recovering from a disaster without the fast reverse process
Use this procedure in place of the fast reverse process. The fast reverse process
allows a FlashCopy relationship to be reversed without waiting for the background
copy of the original FlashCopy to complete.
It is not necessary to use the fast reverse feature of FlashCopy for your recovery.
However, the wait for recovery is significantly longer if you do not.
1. Initiate a background copy on the Volume B to Volume C FlashCopy
relationship.
2. Wait for the background copy to complete. Observe the out-of-sync tracks.
3. Select the Reverse relationship and Initiate background copy options on the
Volume B to Volume C FlashCopy relationship. This reverses the FlashCopy
relationship such that Volume C is the source and Volume B is the target.
152 DS8000 User’s Guide
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