[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Bacula-devel] Vbackup feature


> 5. Like the Migration and Copy jobs, the input Pool (from where it
reads
> the
> currently backed up data) and the output Pool (where it writes the
merged
> data) must be different.  This ensures that the job does not attempt
to
> read
> and write to the same device, which just will not work.

The key point is that Migration/Copy/vBackup/whatever jobs need to be
able to force the selection of a *different* volume in the specified
pool for output, regardless of whether it is the same pool or a
different pool. If that capability is available, the scenario you
discuss is no longer a problem (and it fixes the ability to consolidate
tapes easily within a pool, as long as there is spare space on *a*
volume in the pool different than the one you're reading from).

> However, it is much more likely that you will then continue doing
> incremental
> backups (no more Full or Diffs).  At some point later, you want to do
> another
> vbackup to "consolidate" all the Inc backups, and now the process
fails,
> because you are going to need to read from Pools P2 (Full produced by
the
> vbackup) and P1 (new Incs), and you will attempt to write to P2, which
> will
> not work.
> 
> Thus without some other mechanism to move Volumes from Pool to Pool, a
> setup
> like described above won't work, and I suspect this is what will be
done
> the
> most frequently (i.e. do only one Full and there after vbackups when
there
> are enough Incs to warrant a consolidation).

I would argue that your Vbackup becomes the basis for any future
incrementals and the previous jobs are deleted -- think of it as a
"bring the base up to *this* point in time, and then start work from
there".

This is effectively what TSM does, and it works pretty well. It implies
at some point you will need versioning of objects/files if you want to
allow people to go back in time, but I would be OK with the vbackup jobs
being a one-time consolidation without the ability to go back -- I would
use it to get to a "minimum number of tapes to restore" state every so
often. 


-------------------------------------------------------------------------
Sponsored by: SourceForge.net Community Choice Awards: VOTE NOW!
Studies have shown that voting for your favorite open source project,
along with a healthy diet, reduces your potential for chronic lameness
and boredom. Vote Now at http://www.sourceforge.net/community/cca08
_______________________________________________
Bacula-devel mailing list
Bacula-devel@xxxxxxxxxxxxxxxxxxxxx
https://lists.sourceforge.net/lists/listinfo/bacula-devel


This mailing list archive is a service of Copilotco.