FAQ:What's the difference between a vtape and VFS device?

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This article answers a FAQ (frequently asked question).

vtapes, tapes, and volumes

When Amanda was first written, it only did backups to actual tapes - plastic boxes with long strips of magnetic material. So the word "tape" appears all over Amanda's documentation and messages. Later, Amanda introduced backups to disk. This feature basically emulated tapes on disk, and so these were called vtapes. This name is still used quite often in documentation and on the mailing list.

In general, we try to refer to units of data storage as "volumes". For physical tapes, this means the same thing as "tape". For backups to disk, this means the same thing as "vtape". For Amazon S3 backups, we have always used the term "volume," because "s3tape" just sounds silly.

devices

In Amanda-2.6.0, Amanda introduced a new Device API which completely rewrote all of code to read and write data to storage media. This introduced the concept of a device, which is analogous to a tape drive: a device is a tool to read and write on a volume. Each device has a "prefix" which is used to identify it in an Amanda configuration. Here is a partial list of devices. See amanda-devices(7) for the full, current list.

Tape Device
Real, old-fashioned tapes. Prefix is tape: (or no prefix at all, for backward compatibility)
VFS Device
Backup to disks, a.k.a. vtapes. Prefix is file:.
S3 Device
Backup to Amazon S3. Prefix is s3:.
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