How does Amanda Enterprise backup to disk

This article is for Amanda Enterprise (AE).

Amanda treats writing backed-up data to disk as though it is writing to a tape, and therefore data written to disk by Amanda is referred to as virtual tapes or
“vtapes”. Amanda gives labels and keeps track of virtual tapes just as it does with real ones. Data is written to virtual tapes in a directory named after the
backup set in the path specified by Backups stored at on the Backup| When page. 

AE 3.4:

ZMC creates and manages virtual tapes for you. All virtual tape labels and data files are stored in a single directory named after the backup set in the path specified by Backups
stored at on the Backup| When page. Each backup of a backup object is written to its own virtual tape, and thus multiple virtual tapes are generally used per backup run. When
the backup on the virtual tape is no longer needed to restore data within the specified retention period, it is automatically pruned unless it is the last full backup for that object. In
this case, it is kept indefinitely until manually recycled.