6027-1610 Disk `diskName` is the only disk in file system `fileSystem`. You cannot replace a disk when it is the only remaining disk in the file system.

Explanation
The mmrpldisk command was
issued, but there is only one disk in the file system.
User response
Add a second disk and reissue the command.

6027-1610 Disk diskName is the only disk in file system fileSystem. You cannot replace a disk when it is the only remaining disk in the file system.