If you are using Thin Image, Dynamic Provisioning, and Dynamic Provisioning for Mainframe in a single storage system, note the following when creating Thin Image pairs:
- (VSP 5000 series) Data compressed or deduplicated by the capacity saving function is copied to a volume after compression and deduplication are released. The capacity saving function is not performed immediately for copied data. Before creating or resynchronizing a Thin Image pair, verify that the available capacity in the copy destination volume is greater than the used capacity in the copy origination volume. For details, see the Provisioning Guide for Open Systems.
- If you create a Thin Image pair using a volume with the capacity saving function enabled, the compressed or deduplicated data is copied. Because of this, copy or I/O performance may be degraded.
- When the capacity saving function is used, management information is stored in a pool. As a result, there may be difference between a P-VOL and an S-VOL in the number of used pages or licensed capacity.
- The capacity saving function can be set on the P-VOL or S-VOL of a cascaded or clone pair, but only works on the clone pair. The deduplication system data volume cannot be used as a Thin Image P-VOL or S-VOL.
- You can create a Thin Image pair whose P-VOL or S-VOL is a Dynamic Provisioning V-VOL only if you are not currently expanding the Dynamic Provisioning V-VOL capacity.
- Performing a Thin Image paircreate operation while zero pages are being reclaimed (including reclamation by WriteSame, Unmap command, or rebalancing) results in the zero-page operation being interrupted.
- When the WriteSame or Unmap command is issued to the P-VOL or the S-VOL for a Thin Image pair, zero pages are not reclaimed by the command.
- If the Unmap command is issued to the Thin Image virtual volume, the command ends abnormally.
- Thin Image pair creation might be rejected if the Unmap command operation is in progress with system option mode 905 ON. Wait a while and then retry the operation. If the operation still fails, set system option mode 905 to OFF and try again.
- You can use a maximum size Dynamic Provisioning volume as a Thin Image P-VOL or S-VOL. For information about the maximum size for Dynamic Provisioning volumes, see the Provisioning Guide for your storage system.
- For details about whether zero pages can be reclaimed when you specify Thin Image P-VOLs or Thin Image S-VOLs on Device Manager - Storage Navigator or Command Control Interface, see the the Provisioning Guide for your storage system.