You can use Thin Image to overwrite snapshot data in pools to P-VOLs so that the P-VOL content is returned to the condition it was when you stored snapshot data.
Overwriting snapshot data to P-VOLs is also referred to as restoring Thin Image pairs.
If data is written to a secondary volume, this particular data (not snapshot data) is overwritten to the primary volume when the Thin Image pair is restored.
If a problem occurs in P-VOL data due to a failure, restoring the pair restores the P-VOL data saved when the snapshot data was stored. However, if the pair status is PSUE, the pair cannot be restored.
The time for restoring a Thin Image pair depends on the following, even if the pair synchronization rate is 100%:
- The amount of pool capacity a pair is using.
- The number of pairs being operated concurrently.
The pair synchronization rate shows the rate that S-VOL data matches that of the next generation of the S-VOL. If the S-VOL is the latest one, the synchronization rate is computed by comparing the S-VOL with the P-VOL.
For the Thin Image pair where the cascade attribute is enabled, the information displayed in Synchronization Rate (%) of the View Pair Synchronization Rate window varies depending on the pair status.