Overview

Data centers use various methods to track the storage location and external identification of removable media. Some data centers use a volume serial number to refer to a specific volume. Other data centers refer to tapes by slot IDs (corresponding to physical storage slots) or by volume groups (corresponding to application, and so on.)

Control-M/Tape identifies volumes in its Media Database by volume serial number (volser). These volsers are usually physically recorded in a volume’s internal label when the volume is initialized. Volsers should always be unique within a single site.

Many data centers regularly receive volumes from other sites. In some cases, these volumes may have the same volsers as volumes already in use at the data center. This creates a duplicate volser situation. The mechanism used by Control-M/Tape to handle duplicate volsers is described in under Duplicate Volser Considerations.

Control-M/Tape enables users to check in external volumes, either through the Online facility, or through an Automatic Check-In process. These volumes are marked as External Volumes in the Media Database. They are processed through the same management, control, and protection procedures as local volumes. External volumes are considered a separate tape pool (call EXTERNAL). The Control-M/Tape Retention Management utility (CTTRTM) lists the EXTERNAL pool separately in its Scratch report. This makes it easier to track expiration of external volumes.

When an external volume reaches its expiration date, it can either be deleted from the Media Database or it can be handled like regular volumes, which are marked SCRATCH but remain in the Media Database.