Changing the MP unit assigned to an LDEV

Before you begin

The Storage Administrator (System Resource Management) role is required to perform this task.

• Changes to the MP unit ID of an LDEV should be made during off-peak hours when the I/O load is as low as possible. Before and after changes are made, it is recommended that the cache write-pending rate (%) for all CLPRs is lower than 50%. Do not change the MP unit ID when the I/O load is high -- for example: during initial copy of ShadowImage, TrueCopy, global-active device, or Universal Replicator.

• When you change the MP unit ID of an LDEV, you should use Performance Monitor before and after the change to check the load status of devices. Do not change several LDEV MP unit IDs during a short period of time. As a guideline, you can change 10% or less of the total number or the full workload of LDEV MP unit IDs assigned to the same MP unit ID at the same time.

• After you change the MP unit for an LDEV, wait more than 30 minutes before you try to change the ID again for the same LDEV.

Procedure

1. Open the Logical Devices window.

In Command Suite:

1. On the Resources tab, click Storage Systems, and then expand All Storage Systems and the target storage system.

2. Right-click Volumes, and then select System GUI.

In Device Manager - Storage Navigator:

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

2. Click Logical Devices.

2. In the Logical Devices window, select the LDEV ID of the LDEV that has the MP unit you want to change.

3. Click More Actions, and then select Assign MP Unit.

4. In the Assign MP Unit window, specify the MP unit in MP Unit.

5. Click Finish.

The Confirm window appears.

6. In the Task Name text box, 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.

7. Click Apply.

If the Go to tasks window for status check box is selected, the Tasks window appears.