Amanda-Users

Re: Tape backup from server disk

2007-03-11 18:16:07
Subject: Re: Tape backup from server disk
From: Jon LaBadie <jon AT jgcomp DOT com>
To: amanda-users AT amanda DOT org
Date: Sun, 11 Mar 2007 18:08:28 -0400
On Sun, Mar 11, 2007 at 05:42:15PM -0400, FL wrote:
> I'm using AMANDA to back up a disk that is periodically rsynced from
> a NAS. At a certain point in the backup, amdump complains that it doesn't
> have enough diskspace, persumably for the holding disk. Is this something I
> should be concerned about?
> 
> Since the files are on a disk on the tapebackup server, I don't need a
> holding disk: I just want the tape backup to read the files from disk as
> they are needed; they don't need to be copied to a holding disk, as if the
> backups could be speeded up by sending them over a network to the server's
> holding disk.
> 
> How do I ensure the desired behavior for this setup? Am I missing the point
> (no doubt I am, and no doubt it's the crucial point).
> 

When using virtual tapes (disks) to store amanda dumps,
amanda still acts as if it were going to a physical tape
with a single data stream.  The purpose of a holding disk
in this case is to allow multiple dumps run simultaneously
to the holding disk.  As each completes it is transfered
to the vtape, a very fast operation.  Thus the overall
time for backup should be shorter due to many running in
parallel to the holding disk rather than one a a time
going at dump rate (not disk to disk rate) directly to vtape.

-- 
Jon H. LaBadie                  jon AT jgcomp DOT com
 JG Computing
 4455 Province Line Road        (609) 252-0159
 Princeton, NJ  08540-4322      (609) 683-7220 (fax)