
                  Chapter 7. Tapetypes
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Chapter 7. Tapetypes


Note

Refer to http://www.amanda.org/docs/tapetypes.html for the current version of
this document.
Several tapetype definitions are available in example/amanda.conf 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 amanda.conf.
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.

Note

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.
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