Chapter 2 Data Replication
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If the power to the disk array is turned off for maintenance, access to the disk array is disabled,
disallowing to continue copy operation for the paired volumes in the disk array. In this situation, the
data replication function for the disk array stops replication operations of the whole disk array.
Freezing of replication operations for the disk array due to power down of the disk array is called
freezing of the disk array and the state is called the freeze state of the disk array.
When a disk array is in the freeze state, replication operations between volumes to which the pair
setting with the volume in the disk array is specified are also suspended, and the copy control state of
the pair becomes the freeze state.
When the pair is in the freeze state, no new replication operation can be performed.
For pairs in the freeze state, note the following.
• Freeze in the Separate state
If the pair goes into the freeze state in Separate execution, it transits to the Separate state due to a fault
(failure separation) when the following operation is performed.
<When updates to MV are done to the area where copy to RV has not been completed>
In this case, to use RV after the freeze state is cancelled, you must perform Replicate again to copy
data, and perform Separate.
• Freeze in the Replicate state
If the pair goes into the freeze state in the Replicate state, copy operation between MV and RV is
suspended. Copy operation is automatically resumed when the freeze state is cancelled.
• Freeze in the Restore state
If the pair goes into the freeze state in the Restore state, I/O terminates abnormally when reference or
update is performed to the area where copy from RV to MV has not been completed.
If the pair goes into the freeze state in the restored state, copy operation between MV and RV is
suspended.
Copy operation is automatically resumed when the freeze state is cancelled.