Scratch volumes

A scratch volume is an optical volume that is not yet associated with an Object storage group or an Object Backup storage group.

If an optical volume is not pre-formatted and labeled, it must be labeled with a unique volume serial number before it can be accessed by OAM. This task can be completed in either of two ways:

Labeling an unlabeled optical disk on an operator-accessible optical disk drive in response to a LABEL command which is entered by the operator
Labeling an unlabeled optical disk on a library-resident optical disk drive as a result of being inserted into the input/output station of an optical library

In either case, the operator is asked to supply the volume serial number for each side of the optical disk. The volume labels are written and rows are created in the volume table in the OAM configuration database. The volumes are marked as scratch volumes or grouped volumes depending on how the operator replies to the CBR4432D message during label processing.

Both sides of a scratch volume become either grouped or backup volumes when a scratch volume is used to satisfy an out-of-space condition in an Object or an Object Backup storage group.

Note: Because WORM optical volumes that are full or have very little free space are not as useful as scratch volumes, the operator is notified by message CBR4451I if the kilobytes that are free are less than the SCRENTRYTHRESHOLD parameter. The message contains the number of kilobytes that are free and the percentage of free space that this represents on the volume. This gives the operator the opportunity to fail the cartridge entry process by responding through message CBR4452D, thus causing the cartridge to be ejected from the library.