On Fri, Apr 01, 2005 at 10:19:07AM +0200, Erik P. Olsen wrote:
> On Fri, 2005-04-01 at 02:06 -0500, Jon LaBadie wrote:
> > 
> > Just for my own interest ...
> > 
> > Why do you want to do your own scheduling when amanda
> > often does a far superior job to human defined scheduling.
> 
> Hm. I would like to challenge this statement.

I don't normally bite on challenges, but I'll take up this one.

I hope you read into my statement that I meant amanda vs human,
both using the amanda 'manager and scheduler' software.  I say
it that way as amanda is not a backup "program".

> It may be true if you have a large network of systems to back
> up but if you only have one system I doubt if it's true.

Did you miss that amanda is an acronym for:

   Advanced Maryland Automatic NETWORK Disk Archiver

The needs of a site with one system are very different than those
of a site with a network of systems for which amanda was intended.
The fact that it can be used very effectively on a single system
is a testament to its flexible design.

> Before my switch to Linux I backed up my system
> (OS/2) on a weekly schedule with one full back-up and four incremental
> back-ups to one tape only. It worked extremely well, if I crashed my
> system - which I did very often - it took me about half an hour to
> recover either using a stand-alone recover program or my maintenance
> OS/2 if it was alive and I kept an archive of up to 8 weeks of back-ups.
> Now with Linux and Amanda I use 9 tapes mainly because Amanda won't add
> today's back-up to yesterday's tape. I could probably do with less tapes
> but I feel more confident with a large tape pool. 

On my home site I do have amanda backup more than one system.  But I only
care about one.  The others are "test" systems.  I will often reinstall the
OS from scratch on them.  For example, I have HP-UX and Tru64 unix systems
just because I have clients who use those OS and I like having one available
to practice with.

The one host I do care about has about 150GB of disk with about 40GB filled.
One thing that may be different from your environment is that I've broken it
down into about 15 DLE's.  By keeping the DLE's small individually, amanda's
scheduler can balance when to do level 0's of each DLE throughout the dumpcycle
and lets me do daily backups to a single DDS3 tape.  Even when I've downloaded
a couple of new CD's, amanda adjusts and rebalances its schedule seldom
requiring two tapes in a day.

I have not worked with OS/2 for over a decade.  From that experience I recall
a backup "program", analogous to dump or tar.  I don't recall a backup "system"
one that for example tracked the tapes used and reused them in the correct 
order,
maintained indexes of files on which tapes, had interactive or batch recovery,
dynamically and automatically adjusted for missed backups or tape errors,
allowed for flexibility in time between level 0's on a file system by file 
system
basis, adjusted the incremental level based on the amount of change in the file
system, ...  The OS/2 backup program I remember did nothing more than I can do
with dump and a little shell scripting.  Was there a backup "system" added to
OS/2 of which I'm unaware?  What features of that system did you find useful?

> 
> I would add that I haven't yet found out how to keep a repository of
> back-ups of the previous weeks like I was used to with OS/2. I like the
> safe feeling of having a set of back-up tapes from which I know I can
> recreate the system as it was on a specific day. Now I just have my 9
> tapes used in a round Robin fashion.

I too am more confident with a large tape pool, but I have 24 in rotation,
rather than 9.  With that collection I find it simple to recover files as
of a specific date anytime within the last 3-plus weeks.

I'm a keyboard user from wayback.  Literally mice did not exist when I started
with unix.  There are times when I must deal with email using a GUI program like
ThunderBird or (horrors) LookOUT.  They make me use the mouse and I hate it.  I 
go
back to my prefered, mouse-less program, mutt as soon as possible.  I have 
always
felt that one should use what meets their needs and with which they are 
comfortable.


Amanda is certainly not the answer for every backup requirement.  For one 
current
client I'm using rsync to meet their needs and comfort level.  Based on your
described use of your backups and your lack of comfort with amanda's scheduler,
might not a set of shell scripts and dump or tar be a suitable, perhaps superior
solution for your needs than amanda?

-- 
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)