Amanda-Users

Re: Different tapetypes

2005-04-01 03:01:56
Subject: Re: Different tapetypes
From: Gene Heskett <gene.heskett AT verizon DOT net>
To: amanda-users AT amanda DOT org
Date: Fri, 01 Apr 2005 02:53:46 -0500
On Friday 01 April 2005 01:46, Belen Isla wrote:
>Hi all,
>
>I am trying to configure amanda to backup my system and I would like
> to use two different types of virtual tapes in a single
> configuration file, I mean, I would like to use big virtual tapes
> for full backups and smaller ones for incrementals. Is it possible
> to use the parameter tapetype twice in the amanda.conf file? In
> affirmative case, how can I associate a virtual tape with the
> appropriate type?
>
>Thanks.
>
>Belén.

I believe that to do that, you would have to setup two seperate 
configs.

However, this leads to the scenario where you are forceably bending 
amanda to a backup framework that it wasn't really designed to 
handle.
[amanda@coyote Daily]$ amadmin Daily balance

 due-date  #fs    orig MB     out MB   balance
----------------------------------------------
 4/01 Fri    7      14973       9433    +33.3%
 4/02 Sat    8      11697       5147    -27.3%
 4/03 Sun   22      12492       7273     +2.8%
 4/04 Mon   10       8521       6449     -8.8%
----------------------------------------------
TOTAL       47      47683      28302      7075
DISTINCT    44      46519      27687

Amanda has a very good scheduler, and that schedulers task is at least 
2 fold.

1.  Given sufficient storage capacity, it will do a full backup of 
everything in the disklist at no more than dumpcycle days interval.

2.  To that end, amanda will move the schedule for an individual 
disklist entry up in order to fill a run thats quite small otherwise.

The background framework for this scheduling dance comes into play 
after amanda has had time to develop a bit of history for the 
individual disklist entries as amanda juggles things trying to 
achieve a balance of using nearly the same amount of tape (or disk) 
for each run.  After the system has stabilized, its quite common to 
see that it filled the tape to 98% of the tapes capacity last night, 
which is nice, until you also note that it hasn't hit an EOT error in 
a long time.  Then you are rightfully impressed I hope.

If you leave amanda alone, and let amanda work out her own schedule, 
she is capable to doing a much better job than we can when we attempt 
to bend amanda to our will.

After all, if you have a dumpcycle of 7 days, then the recovery will 
need a maximum of 7 days worth of tapes.  But for a specific entry in 
the disklist, that ones level 0 backup might be on last nights tape.  
When you ask it for that, amanda will know which tape contains what 
and the actual amount of tape shuffling to do the recovery is 
probably going to result in each tape being loaded several times 
anyway.

Just let amanda do its thing, its uncommonly good at what it does.

It will help amanda quite a bit if the individual disklist entries are 
much smaller than the tapetype is set for, because in that manner 
amanda can make, over a period of time, quite fine-grained 
adjustments.  I'm using a 200GB disk here, with a 4 day dumpcycle, 
and a balance report tells me amanda hasn't quite settled yet since 
my last adjustment a week ago.
[amanda@coyote Daily]$ amadmin Daily balance

 due-date  #fs    orig MB     out MB   balance
----------------------------------------------
 4/01 Fri    7      14973       9433    +33.3%
 4/02 Sat    8      11697       5147    -27.3%
 4/03 Sun   22      12492       7273     +2.8%
 4/04 Mon   10       8521       6449     -8.8%
----------------------------------------------
TOTAL       47      47683      28302      7075
DISTINCT    44      46519      27687

The friday run will overflow the tapesize I have set by about 1.5GB, 
so some of that will get pushed off till the saturday run, which has 
plenty of spare space.  However, amanda will not willingly delay 
anything more than 1 day.

-- 
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)
99.34% setiathome rank, not too shabby for a WV hillbilly
Yahoo.com and AOL/TW attorneys please note, additions to the above
message by Gene Heskett are:
Copyright 2005 by Maurice Eugene Heskett, all rights reserved.

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