In IBM DS/DCS storage, The preferred controller ownership of a logical drive or a array is the controller of an active-active pair that is designated to own the logical drives.

The preferred owner for a logical drive is initially designated when the logical drive is created. If the preferred controller is being replaced or undergoing a firmware download, or FC path problem etc.. ownership of the logical drives is automatically shifted to the other controller. That controller becomes the current owner of the logical drives. 

When you fixed the problem, you want to return the logical drives to their preferred controller owners. This change is considered to be a routine ownership change and is reported in the Event Log.


To redistribute logical drives to their preferred controller:

 

Use this SMcli command:

SMcli Ctrl-A-ip Ctrl-B-ip  -c 'use password ""; reset storageSubsystem logicalDriveDistribution'

Or via SMclient GUI

Storage --> Logical Drive --> Advanced -->Redistribute Logical Drives

 

Important:

1. If you run this command without a multi-path driver on the hosts, stop I/O activity to the logical drives to prevent application errors.
2. You cannot run this command if all of the logical drives are currently owned by their preferred controller, or the storage subsystem does not have defined logical drives.
3. Under some host operating systems, you must reconfigure the multi-path host driver. You might also need to make operating system modifications to recognize the new I/O path to the logical drive.