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Re: Some Questions about holding disks and compression
2005-10-21 08:51:05
On Fri, 21 Oct 2005 at 10:22pm, Jeff Allison wrote
Most of the disk that I back up are on the same server that the backups are
running on, I'm using comp user tar for most of them, I only have a small
holding disk 4GB that most DLE's will fit on but three of them will not.
What I really want to know is does using client or server compression make
any difference on local DLE's and if the DLE will not fit on the holding disk
should I use "holding disk no".
For local DLEs client=server, so the end result of either will be the
same. And, if the DLE won't fit on the holding disk, amanda won't try, so
saying 'holding disk no' won't make much of a difference.
The one caveat to the above statement is for new DLEs. Amanda assumes a
50% compression ratio for new DLEs. So if 50% of the estimate size will
fit in the holding disk, amanda will try to do that. If the actual
compression ratio differs, it may run out of room and have to start over
straight to tape. You can adjust amanda's initial guess at the
compression ratio by using 'comprate' in the dumptype.
Also two of my DLE's are the data dirs of server systems that should really
be shut down while the backup is in progress, is Amanda capable of this???
There are 2 ways to do this. The first (coarse grained, but easier) way
is to have cron call a script rather than amdump directly. The script
would shut down the data dirs, run amdump, and then start the data dirs
back up when amdump is done. The obvious disadvantage is that the data
dirs are down the whole time amdump is running, not just when they're
actually being backed up.
The other (more fine grained, but trickier) way is to have amanda call
scripts on those clients rather than dump/tar directly. Those scripts
would then do the data dir shutdown/backup/restart dance.
--
Joshua Baker-LePain
Department of Biomedical Engineering
Duke University
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