You may find tapetype-definitions in the example
amanda.conf, in the
mailinglist-archives of the amanda-users-mailinglist at http://marc.theaimsgroup.com/?l=amanda-users
or in the Amanda-FAQ-O-Matic at http://www.amanda.org/fom-serve/cache/1.html.
They inform Amanda how much it is supposed to be able to store in a
tape (length), how much space is wasted at the end of a dump image
with the EOF mark (filemark) and how fast the tape unit is (speed).
The most inportant parameter is length, since Amanda may decide to delay a backup if length is too small, but, if it is too large, Amanda may end up leaving dumps in the holding disk or having to abort some dump.
Filemark is important if you have many disks, particularly with small incremental backups. The space wasted by so many filemarks may add up and considerably modify the available tape space.
The speed is currently unused.
If none of the sample tapetype entries match your needs, you may search the mailing list archives or look up the on-line list of tapetype entries. Just follow the links from http://www.amanda.org.
Amanda provides the amtapetype utility to calculate the size of a tape,
to generate a "tapetype" entry for your
Specifying the appropriate tape device, but beware that it may take many hours to run (it fills the tape twice ...). Make sure you do not use hardware compression, even if you plan to use hardware compression in the future. amtapetype writes random data to tape, and random data will expand instead of compressing, therefore you'll get an estimate that's smaller than expected.
Please note that amtapetype in releases up to snapshot 20040915 expects to be given a tape that can be overwritten without causing harm.
It does NOT warn you if the tape contains a label or data. amtapetype will OVERWRITE the tape so be cautious. You have been warned.
Snapshot 20040915 introduces a warning and the flag -o to overwrite a labelled tape.