<snip>

> Because in amanda, they don't write to the tape drive.  Other 
> programs do.  There are several possible reasons, I'll 
> mention only one.  How do you have 20 client hosts all 
> dumping simultaneously to the same tape drive and use those 
> program's multi-tape feature?

Um.

I thought Amanda got dump images from clients in parallel, and put them
on the holding disk, and _then_ wrote these out to the tape, one at a
time... I didn't think that the images were interleaved on tape. What
does amanda use to write to tape? I *think* it uses dd, but can't quite
tell... That would explain why it couldn't split backups across tapes.
(Am I correct?)

> 
> > My problem is that I (am planning to) have a single 
> filesystem, which 
> > will be around 300Gb in size, but I have a choice between 
> DLT4000 and 
> > DLT7000 tapes, at 40 or 70Gb each. I guess I can do the work-around 
> > that Jon LaBadie mentioned later in the email I quoted 
> above, but I'd 
> > rather not, if I can avoid it. If I have no choice, then 
> rather than 
> > explicitly listing X different DLEs, I'd rather be able to 
> say /BIG/*, 
> > and have amanda figure out how best to order them. Is that possible?
> 
> 
> Lots of amanda users split according to the procedure I 
> outlined. My /BIG is only 40GB.  But then my tape is onle 
> 12GB.  I'm sorry it will be a "pain" to set up.  Then again, 
> after the 5 minutes it took me to do it 3 years ago, I 
> haven't had to do anything about it since.  That is a minor 
> part of the configuration.

OK, it seems that perhaps I am carrying some Legato baggage with me. I'm
new to amanda, you see. When I plan a backup system, I'm used to trying
to do it in a regular fashion, say with a full dump of everything on the
weekend, followed by daily incrementals. I'm used to being able to take
my weekend tapes offsite as an offsite archive, so if everything burns
down, I can go back to my most recent offsite tapeset, and restore
everything from there, and get a consistent system.

After reading a bit here, and some other doco, I think I might have
discovered that my assumptions about amanda are slightly wrong. I
suppose also, that my particular needs are slightly different to most
peoples, in that I have (or will soon have) a single large data
partition of around 200Gb, and it is likely to be on the same server
that the tape robot is attached to.

Anyway, it seems that what I need to do is use DLEs to split my big
partition into sub-trees to back up, allow amanda to do its thing on a
daily basis, perhaps, and then weekly, use a different amanda config
(with the same disklist) to do a full dump, which i can then take home
for offsite archive purposes.

rr

-- 
Richard Russell
Yellow Goanna P/L
m: +61 412 827 805
e: richard AT yellowgoanna DOT com
w: http://www.yellowgoanna.com