Amanda-Users

Re: questions regarding incremental backup sizes

2006-11-17 22:24:11
Subject: Re: questions regarding incremental backup sizes
From: René Kanters <rkanters AT richmond DOT edu>
To: Gene Heskett <gene.heskett AT verizon DOT net>
Date: Wed, 15 Nov 2006 10:16:22 -0500
Hi Gene,

Sorry about not hitting reply-all. I will from now on!

So are there instructions regarding the best way to set up amanda to do backups to a disk as opposed to tape? I found the sample for using the test environment with virtual tapes at http://wiki.zmanda.com/index.php/Test_environment_with_virtual_tapes

I took out the holdingdisk part of that amanda.conf since I assumed that since I am writing directly (and only) to a disk, that would not be needed, but your comment suggests that that may not be the proper way to think about it.

By the way, where can I look at the mailing list archives to try to find my answers there?

Cheers,
René


On Nov 15, 2006, at 8:09 AM, Gene Heskett wrote:

On Wednesday 15 November 2006 07:50, René Kanters wrote:
I've added the list back, please use 'reply all' when replying to any
mailing list.  That way, the list archives can be searched with a very
high probability of finding an answer to the problem you have because
someone else already had it and most likely solved it. Which is true for
both problems you have asked about so far. :-)

Hi Gene,

Thanks, that was indeed it.

I was wondering whether you know why I get in my amdump.1 a lot of

find diskspace: not enough diskspace. Left with 1952 K
driver: find_diskspace: time 0.138: want 1952 K

and now that my incremental ones are working I get for an increment
backup the similar message

driver: find_diskspace: time 0.142: want 64 K
find diskspace: not enough diskspace. Left with 64 K

while my test tapes are 5MB and only backing up a set of files that
is 2MB big.

By default, the holding disk area is 100% reserved for incrementals. To use it and its highly recommended to save shoe-shining wear and tear on the drive, you should change the keyword Reserved in your amanda.conf to
allow it to be used for fulls too.  I use 30% here.

This 'holding disk' is a buffer area/directory on one of your hard drives that is used as a scratchpad area, where files being compressed are built up until that particular disklist entry is completed, at which point it
is all written to the tape at the tape drives (or the interfaces) full
speed.  Without such a holding disk area setup and in use, any backup
that involves compression will be written as the compressor spits it out, so the drive will be stopped and started many times, trying to recue back to where it wrote the last data each time. This wastes considerable time
and multiplies the wear on the drive by quite a bit.

--
Cheers, Gene
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Yahoo.com and AOL/TW attorneys please note, additions to the above
message by Gene Heskett are:
Copyright 2006 by Maurice Eugene Heskett, all rights reserved.



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