Dynamic Provisioning

You can create a Universal Replicator pair by specifying a DP-VOL (Dynamic Provisioning virtual volume).

  • DP-VOLs can be used for either the UR P-VOL or S-VOL, or both P-VOL and S-VOL.

    A DP-VOL with the capacity saving enabled can be used as a P-VOL or S-VOL of a UR pair. The deduplication system data volume cannot be used as a P-VOL or S-VOL of a UR pair, or as a journal volume.

    When the UR pair using a DP-VOL with capacity saving disabled is in COPY status, the P-VOL capacity saving can be enabled. Capacity savings of a UR pair P-VOL does not begin until after the pair status changes to something other than COPY.

  • DP-VOLs cannot be used as journal volumes.
  • When a DP-VOL is used for a UR P-VOL or S-VOL, the UR of the allocated pages for the DP-VOL is included in the UR licensed capacity. If the actual licensed capacity exceeds the available licensed capacity, you may use UR for 30 days. After 30 days, UR pairs may only be split or released.

    The UR licensed capacity for a volume with capacity saving enabled is the capacity before savings.

  • When you specify a DP-VOL that has allocated pages to a UR S-VOL, the used pool capacity will become temporarily larger than the actual capacity, because pages must be reallocated in the DP-VOL. Therefore, before creating the pair:
    • Make sure that DP-VOL pool capacity is sufficient.
    • Make sure that the pool-VOLs, which are added to a pool, are not blocked. If the pool-VOLs are blocked, restore the volume status and then create the pair.
  • If you want to use DP-VOL s that are also used by ShadowImage or that are in a Volume Migration migration plan, proceed as follows:
    1. Delete the ShadowImage pair or disable the Volume Migration setting.
    2. Create the UR pair.
    3. Re-create the ShadowImage pair or the Volume Migration migration plan.
  • When a DP-VOL is used as the UR S-VOL, you might not be able to update the UR S-VOL because the capacity of the pool-VOL is full. In this instance:
    • The pair is suspended.
    • With RAID Manager, the UR pair status changes to PFUS.
    • In Device Manager - Storage Navigator, the UR pair status changes to PSUS.
  • When both of the following conditions exist, pages that do not exist in the P-VOL might be assigned to the S-VOL when splitting and then resynchronizing the pair:
    • The copy pace is Faster.
    • The pair is created and the pair status is COPY.

    To delete S-VOL pages that do not exist in the P-VOL, use the Reclaim Zero Pages function for the DP-VOL.

  • 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 UR 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 for Open Systems.
  • If you create a UR pair using a volume for which the capacity saving function is used, compressed or deduplicated data is copied. Copy or I/O performance might be degraded because of this.
  • When the capacity saving function is used, management information is stored in a pool. As a result, there might be differences between a P-VOL and an S-VOL in the number of used pages or licensed capacity.