Greetings:
I am setting up Amanda and am trying to get the configuration mostly
right the first time. I like to understand what I'm doing, and not
ask really obvious questions. To that end, I've read the chapter in
the backup book, read most of the man pages, most of the files in
doc/*, a bunch of entries in the Faq-O-Matic, and a couple hundred
posts in the archive for this mailing list. Hopefully that gets me
started, but please accept my apologies if this still seems obvious.
I a couple servers and about a dozen PCs to backup. Based upon my
current backup, it seems that only a few GB changes every day. I have
a 20 tape DLT 80 autochanger, which should back everything up for a
long time. My tape machine also has "plenty" of holding disk space
(something like 3 tapes worth/120 GB). The servers have quite a bit
of disk space on them, but the vast majority of it never changes (1
server has maybe 100 GB total space that needs to be backed up, but 80
GB of it is basically static).
My configuration is therefore one which will waste a lot of tape if I
let Amanda write a tape every night (and more importantly, it will run
out of tapes and pester me in 3 weeks instead of 6 months...)
According to the FAQ-O-Matic:
-----
This can be wasteful, specially if you have a small amount of data to
back up, but expensive large-capacity tapes. One possible approach is
to run amdump with tapes only, say once a week, to perform full
backups, and run it without tape on the other days, so that it
performs incremental backups and stores them in the holding disk. Once
or twice a week, you flush all backups in the holding disk to a single
tape.
-----
Inspired by what I think that is telling me, I would like to do is
something like this:
- Run compressed backups to the holding disk
- while the holding disk has > 1 tape worth of data (40 GB), write a
tape.
It isn't clear to me how to set it up to get this behavior. It seems
like I might be able to get it by having two configurations, but then
it isn't clear of the tape tracking database features will work like I
would like (i.e. if one configuration writes to the disk only, and
another sometimes pushes the disk to a tape, will the database know
which tape the files from the disk only configuration are on?)
It almost seems like I should mess with tape changer scripts so that
requests for tapes are automatically failed if there is less than 1
tapes worth of information on the holding disk. Once there is, it
could give Amanda 1 tape, and things might proceed the way I want.
Have I missed something obvious, or am I on the right track?
I appreciate any opinions, pointers to documentation, etc. that anyone
might provide...
Thanks,
Bret
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