[rescue] Re: how to utilize multiple tape drives in the same library/silo with Amanda...

[nick at snowman.net]

Ahh, thanks for reminding me of another amanda killer on real FSs.  Amanda
wants a FS as big as your biggest FS to buffer in.  That's irrational on
most real sized (.5tb+) file systems.  Works fine for most hackers, but
that's a hell of a limit.  I know you can skip it, and I've never
personally benchmarked w/ cache FS vs w/o cache FS, but the amanda FAQ &
docs make it very clear that a cache FS is nearly required (it's entirely
possible that that requirment is no longer real, and the docs just havn't
been updated, but amanda should still be able to do partial FS
cacheing).  I also don't see useing multiple configs in parallel as an
optimal solution to multiple drives.  Yes it works, mostly, as long as
you're not (again) backing up one large FS, but even then it's a PITA and
splitting your library is very suboptimal at least for me.  I've only got
40 slots and I've got 4 drives, that leaves (assumeing equal
split) 10tapes/drive.
	Nick

On Mon, 22 Jul 2002, Greg A. Woods wrote:
> Did my message not get through to you?
> You run multiple configs, in parallel, if desired (and capable).
> Eg. /etc/amanda/DailySet1/* and /etc/amanda/DailySet2/*
> Each share the same changer device (presumably your library has a SCSI
> conected changer), but you split the tape rack(s) between them and of
> course specify a unique tape drive device in each.  Obviously you need
> different holding disks and other such common stuff too.
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