Hi,
On 21.09.2005 20:32, Bennett, Silas (GE Infrastructure) wrote:
Isn't this what the scratch pool is for?
That's what I suppose, too.
I have to admit that I haven't got it working yet, but I wasn't sure if the scratch pool
was one of those "Features" in the manual, that was not in the Stable version
of the bacula code.
Same here :-)
Cheers,
Silas
=0)
-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] Behalf Of Joe Rhett
Sent: Wednesday, September 21, 2005 11:28 AM
To: Arno Lehmann
Cc: bacula-users@lists.sourceforge.net
Subject: [Bacula-users] Auto-labeling volumes depending on
tape-in-drive?
Okay, Arno, you seem to know the most about the labelling so let's throw
this at you.
Thanks. Nice compliment, but that impression might only be due to the
fact that I was the first to discuss your problem...
Obviously, with disk-based volumes, you have to not auto-label, or limit
the number of volumes in the pool or it will keep growing. The physical
reality can be created very quickly. But with tapes you do have the
simple constraint of "is there really a tape for this?"
Is it possible to constrain bacula to only create volumes when it has a
blank tape in the drive to label? This whole thing with creating a volume
that has no physical reality is what confuses me.
I don't know if this is possible, but I guess that it might be a little
more difficult. Coincidentially, I'm just working on a DVD writer setup,
and there you find the same problem - Bacula has to first "invent" the
volume, and write to the physical disk afterwards.
The problem is that the "tape label" exists in two places: baculas
catalog and on the storage media. The SD can't create a label without
the DIR, and once the DIR is asked to create a new volume, that volume
is in the catalog. (You could, probably, change the protocol in a way
that the new volume would need to be confirmed or deleted after
creation, but that wouldn't really solve all associated problems - one
issue being the fact that the catalog should always represent what
volumes do exist.) (Forget the last sentences if they were not clear
enough...)
Look at tape in drive.
1. If tape is new, auto-label it and use it.
2. If tape is available for recycling, recycle it and use it.
2. following the normal rules concerning recycling, of coures - is it
enabled, retention times, reuse oldest volume first etc. Or, in other
words, in many cases there will be an intervention necessary anyway.
Apart from that - possible, why not. Apart from the above points, of
course. Still, I think that this scenario doesn't help most tape users:
Either you've got a limited number of tapes bacula should use, and label
these once you put them into your setup. Or you've got an autoloader,
and have the tapes labeled in a batch using the 'label barcodes' command.
Anyway, while I understand what you want, I don't think this is a
feature many tape users would use. I'd rather change the manual to state
that automatic volume labeling is recommended with disk (and DVD) use
only ;-)
Of course you can always point out why this feature is important and ask
someone (Kern) to implement it, but you should be prepared to lead a
longer discussion - or to implement it yourself. Of course, _that_
discussion is better done on bacula-devel.
All this assumes that I didn't miss some configuration setting which
allows what you want, of course.
But never "just make up a volume" without having a physical reality...
Good point, also concerning DVDs... but that's another story.
Obviously, with autochangers you'd want to scan through the library and
find the "best tape" based on the above logic...
That's what baculas 'label barcodes' function and the usual tape
selection algorithm do, I'd say. Only it doesn't search for unlabeled
tapes and labels them automatically (which, by the way, would mean big
trouble if you shared a library with another backup application).
Arno
--
IT-Service Lehmann [EMAIL PROTECTED]
Arno Lehmann http://www.its-lehmann.de
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