8–2 Troubleshooting
Hitachi Simple Modular Storage Copy-on-Write SnapShot User’s Guide
Pair Failure
A pair failure can have two causes:
• A hardware failure affecting either the pair volumes or data pool
• A data pool whose capacity is exceeded
To determine the cause of pair failure
1. Check the status of the data pool whose associated pairs’ status is
changed to Failure. For details on checking pair status, see Monitoring
Pair Status on page 7-2.
2. If the status of the data pool is POOL FULL, the pair failure is due to
capacity is exceeded.
3. if the status of the data pool is other than POOL FULL, the pair failure is
due to hardware failure.
The procedure for restoring the pair differs according to the cause.

Recovering from Pair Failure Due to POOL FULL

To recover pairs when status is POOL FULL
1. Delete all the pairs that are using the full data pool.
2. Review SnapShot system configuration. See Chapter 2, Planning and
Design for detailed information on the following:
• Measuring write workload and sizing of the data pool. This
addresses the amount of data your that accumulates in the data
pool and provide calculations for determining the correct size of
the data pool.
• Assessing business requirements to establish the lifespan and
number of V-VOLs
3. Do one or more of the following:
• Increase the size of the data pool. See Assign Volumes for the
Data Pool on page 5-2.
• Reduce the number of V-VOLs
• Reduce the lifespan of V-VOLs
4. Re-create the pairs.

Recovering from Pair Failure Due to a Hardware Failure

To recover the SnapShot system after a hardware failure
1. Review the information log to see what the hardware failure is.
2. Restore the array. See Navigator 2 program Help for details.
3. When the array is restored, delete the pair. See Delete Pairs, V-VOLs,
Data Pools on page 6-7 for more information.
4. Re-create the pair.