Amanda-Users

Re: Is tape spanning documented anywhere?

2006-06-13 12:01:30
Subject: Re: Is tape spanning documented anywhere?
From: Jon LaBadie <jon AT jgcomp DOT com>
To: Amanda Mailing List <amanda-users AT amanda DOT org>
Date: Tue, 13 Jun 2006 11:54:51 -0400
On Tue, Jun 13, 2006 at 05:10:53PM +0200, Toralf Lund wrote:
> 
> I also have one other scenario in mind, though - which is one I've 
> actually come across a number of times: What if a certain DLE due for 
> backup is estimated to be slightly smaller than <runtapes>*<tape size>, 
> and thus dumped to holding disk, but then turns out to be slightly 
> larger?

Wouldn't it be more accurate to say the scenario you ran into previously
was DLE larger than <tape size> because the tape spanning feature was
not available at that time.

> With the current setup, amanda will obviously run out of 
> tape-space during the original dump and also if you try amflush. And if 
> auto-flush is enabled, the next dump will hit end-of-tape before any of 
> the new dumps have been written, and the next one after that, and so on; 
> this holding disk image will effectively block the tape operation of all 
> the following backups, and eventually, the holding disk will be full, 
> too, so amdump won't be able to do anything at all.

What is different with the tape spanning feature is that you could get the
large DLE to tape by simply increasing runtapes, even if only temporarily.
Thus, no system lockup.

-- 
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)