ISM requires that you label and mount a volume before you can use it to back up data. Labeling a volume associates the volume with a specific volume pool and provides ISM with a unique name for tracking and recognizing the media. ISM uses the volume labels to maintain a record of each volume in the ISM catalog. ISM uses the ISM catalog to identify volumes that it needs to back up and recover data.
If you have the Automatic Media Management option enabled for a storage device, you can have ISM automatically label and mount volumes on that storage device. For more information, see Automating Media Management for Tape and Optical Devices. You can also prelabel a volume without mounting it.