Dynamic Provisioning virtual volumes (DP-VOLs) can be used as GAD pair volumes.
A data-reduced volume (V-VOL with capacity saving enabled, DRS-VOL) can be used as a P-VOL or S-VOL of a GAD pair. A deduplication system data volume cannot be used as a P-VOL or S-VOL of a GAD pair.
Note:
- Data compressed or deduplicated by the capacity saving function is copied to a volume after compression and deduplication are released, that is, the capacity saving function is not performed immediately for copied data. Therefore, before creating or resynchronizing a GAD pair, make sure that the available capacity in the copy destination volume is greater than the used capacity in the copy origination volume before capacity saving. For details, see the Provisioning Guide.
- If you create a GAD pair using a data-reduced volume (V-VOL with capacity saving enabled, DRS-VOL), compressed or deduplicated data is copied. Because of this, copy or I/O performance might be degraded.
- Management information about a data-reduced volume is stored in a pool. As a result, there might be a difference in the number of used pages or licensed capacity between a P-VOL and an S-VOL.
- Only allocated page capacity is counted as GAD licensed capacity. However, for data-reduced volumes, the GAD licensed capacity is the capacity before savings. Page capacity or license capacity counted toward the P-VOL and for the S-VOL might differ, because page capacity for the volumes changes according to the operation, for example, reclaiming zero pages.