Using Tertiary Media for Backup and Restore
Tertiary Media is a "backup of a backup" that provides an extra layer of protection for essential data. One way to use tertiary media is to produce off-site copies of backups that are kept on-site for recovery from hardware failure and user errors: if a disaster destroys the office, having offsite copies of backups can save your business.
Amanda provides the amvault (8)utility to create a copy of an existing backup run (identified by date and timestamp). In the context of amvault, the existing source backup is referred to as "secondary media," and the target is the tertiary media.
Using amvault to copy a backup run to tertiary media
Amvault makes one-to-one copies of each piece of media used in a backup run The syntax for amvault is:
amvault [-o Amanda.conf_options] backup_set src-run-timestamp changer label-template
Amanda.conf_options can be any of the options described in amanda.conf (5).
Backup_set is the name of the source backup set.
src-run-timestamp is the timestamp of the backup run you wish to copy. Specify lastest uses the most recent run.
changer is the name of the changer to use as defined by amanda.conf (5).
label-template specifies the string used to prefix the tertiary backup media labels. The string should contain some number of contiguous % characters, which will be replaced with a generated number. Be sure to specify enough % characters that you do not run out of tape labels. Example: DailySet1-%%%
For example, to produce a tertiery backup of MyBackupSet to changer MyChanger with label prefixes of "off-site-N" for the tertiary backup media, you would enter the following command:
amvault MyBackupSet latest MyChanger off-site-%%%
The amvault (8) man page describes these options in more detail.
Restoring from Tertiary Media
When you use amrecover(8) against a backup set, Amanda looks for secondary backup media to restore from first. If none is found, it automatically looks for tertiary media to restore from.