Deleting a tier in a pool

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

To delete a tier in a pool, you must delete all the pool-VOLs in the tier to be deleted. When pool-VOLs in the tier are empty, the appropriate tier is deleted.

If you delete a pool, its pool-VOLs (LDEVs) is blocked. If they are blocked, format them before using them.

You cannot delete the pool-VOL when:

• Creating the pool.

• Deleting the pool.

• Increasing the pool capacity.

• Decreasing the pool capacity.

• Restoring the pool.

• Stopping decreasing the pool capacity.

• Changing the threshold.

• Initializing the pool capacity.

• Changing the external LDEV tier rank.

Notes on deleting a tier in a pool

You cannot delete a pool-VOL under these conditions.

• If the pool-VOL is deleted, the used capacity of the pool volume exceeds the pool threshold.

• If the pool-VOL is deleted, the subscription rate of the total V-VOL capacity, including the control information , exceeds the subscription limit. For details about the formula used to calculate the required pages for one DP-VOL including the control information, see Pool subscription limit.

• There must be 4.2 GB of free space in the pool to delete the pool volumes with system area.

Deleting the pool volume stops the tier relocation. The process resumes after the pool volume is deleted.

To delete a tier in a pool:

1. Perform one of the following to display the Pools window.

For Command Suite:

• On the Resource tab, expand the Storage Systems tree. Right-click DP Pools of the target storage system, then select System GUI.

For Storage Navigator:

• In the Storage Systems tree on the left pane of the main window, select Pools.

2. Select the pool that contains the pool-VOLs to be deleted.

The pool information appears on the right.

3. Select the Pool volumes tab and select all the pool-VOLs contained in the tier to be deleted.

You cannot delete a pool-VOL unless Shrinkable has been applied.

4. Perform one of the following to display the Shrink Pool window.

• Click Shrink Pool.

• Click Actions > Pool > Shrink Pool to open the window.

5. In the Shrink Pool window, verify the changes.

The details of Before Shrinking and After Shrinking, including the pool capacity, the used pool capacity and the free pool capacity, appears in Prediction Result of Shrinking.

6. In the Confirm window, confirm the settings, in Task Name type a unique name for this task or accept the default, then click Apply.

If Go to tasks window for status is checked, the Tasks window opens.