Shrinking a pool

Use this procedure to shrink (decrease the capacity of) a pool. To shrink a pool, you remove the specified pool volumes from the pool. You can shrink up to eight pools at the same time.

Note
  • You cannot shrink a pool when any of the following operations is in process in the target pool:
    • When the pool is being created or deleted
    • When the pool capacity is being increased or decreased
    • When the pool is being recovered
    • When the Shrink Pool operation is being stopped
    • When the threshold is being changed
    • When zero pages are being reclaimed
    • When DP-VOLs are being created
    • When DP-VOL capacity is being increased
  • If you shrink a pool soon after creating or expanding the pool, the shrink pool operation might take a while to complete.
  • If the shrink pool operation is already in progress on a pool, do not issue a CCI command to the same pool to decrease the capacity of the pool.
  • If the pool volumes being removed belong to a parity group that supports accelerated compression, the shrink pool operation takes more time because the unallocated area is formatted and the pages are reclaimed.
  • If you use Device Manager - Storage Navigator to shrink a pool that contains pool volumes from accelerated compression-enabled parity groups, you can delete only the pool volumes that do not belong to accelerated compression-enabled parity groups.
  • When you shrink a pool by removing a pool volume in an accelerated compression-enabled parity group (using HDvM - SN or CCI), the pool auto expansion volumes function is disabled for the parity group to which the specified pool volume belongs. After the pool is shrunk, if you want to enable the pool auto expansion function for the parity group to which the pool volume that was removed belongs, first disable accelerated compression on the pool, and then re-enable accelerated compression on the pool.

    If SIM code 629xxx , 62Axxx, 62Cxxx, or 62B000 (where xxx is the pool number) is reported when accelerated compression of the pool is disabled, enable accelerated compression without performing the countermeasure for the SIM.

Before you begin

The Storage Administrator (Provisioning) role is required to perform this task.

Procedure

  1. Click Storage Systems, and then expand the Storage Systems tree.

  2. Click Pools, and then select the pool that you want to shrink.

  3. On the Pool volumes tab, select the pool-VOL to be removed.

    You can delete the pool-VOL when Yes is displayed in the Shrinkable column.

  4. Click Shrink Pool.

  5. In Task Name, type a unique name for the task or accept the default.

    You can enter up to 32 ASCII characters and symbols, with the exception of: \ / : , ; * ? " < > |. The value "date-window name" is entered by default.

  6. In Estimated Result of Shrinking, review the details of Before Shrinking and After Shrinking, including the total pool capacity, the used pool capacity, and the free pool capacity.

  7. If the estimated result of shrinking is acceptable, click Apply.

    If Go to tasks window for status is selected, the Tasks window appears.
Parent Topic
  • Decreasing pool capacity

    When you want to decrease the capacity of, or shrink, a pool, you delete one or more pool volumes (pool-VOLs) from the pool.