Re: Configuration advise
2005-04-05 04:00:27
This is what I do:
I have a virtual tape device and I use the fact that the "tapes" are
directories and have no fixed size. I have a 400GB disk which is divided
into 20 tapes, each with a tapesize of 80GB. The whole setup depends on the
fact that space not taken up by one "tape" can be used by another because
these are dirwectries within one disk. My ususal daily backup is 5GB-15GB,
but setting tapesize to 80GB ensures that under almost all conditions
amanda will not run out of tape. It's been running smoothly for 2 months.
Shai
Belen Isla wrote:
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.
I have realized that isn't a good idea to change amanda's scheduling.
I'm new using amanda so I have several doubts and I don't know exactly
which is the best configuration option for me. I would like to backup a
single partition of 200GB. Actually it's size is 45 GB, but it can be
increased to reach those 200GB. There is a hardisk available for the
backups of about 700GB so I have configured amanda to use virtual tapes.
I would like also to set the dumpcycle parameter to 4 weeks
(runspercycle=4) in order to do a monthly full backup and 3 incrementals
in between. If the length of the tapes is for instance 175 GB, assuming
that I'm going to use compression, then I can use only 4
tapes(tapecycle=4) and I suppose that is not convenient. Because of this
I had thought in the possibility of using two types of tapes in the same
configuration: big tapes for full backups and smaller tapes for
incrementals that use much less space so I would be able to increase the
tapecycle and keep the backups available more time, but it seems not to
be the best option. Which configuration do you advise me to optimize my
backups? And what about tapesize?
Belén.
--
Shai Ayal, Ph.D.
Head of Research
BioControl Medical BCM
3 Geron St.
Yehud 56100
ISRAEL
Tel: + 972 3 6322 126
Fax: + 972 3 6322 125
email: shaia AT biocontrol.co DOT il
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