> Gordon J. Mills III wrote:
> > Josef, here are some of my comments about TSM that I sent 
> to a lister 
> > off list. I think in a later email I will try to list the 
> things that 
> > I liked about TSM that I would like to see in Amanda. Some 
> may not be possible.
> > 
> > At my previous job we used TSM and it is a very nice backup 
> solution. 
> > We had a tape library that held about 250 tapes and up to 8 
> drives (We 
> > had 5 drives in it). It seems to excel at backing up large 
> amounts of 
> > data. One unique thing it does is that it uses and "incremental 
> > forever" backup strategy. It backs up a machine fully only once (it 
> > can probably be setup other ways, but that's the way we 
> used it)<--(I 
> > could be wrong about that). There is a backup server 
> (similar to the 
> > way Amanda is setup) and it has a database that keeps track of 
> > everything that has been backed up (all files). It knows 
> what files are on what tapes (Also similar to Amanda).
> > 
> 
> One possible downside of the TSM approach is this database.  
> If it is somehow lost or corrupted, all you have is a bunch 
> of tapes with random chunks of data that may not be 
> recoverable into its original structure.  While it is a 
> robust database, things can happen (such as failing RAID or 
> SAN controllers wiping out all of your redundant disks), so 
> you need to make sure that you have backups of the database 
> that are outside of TSM (somewhat similar to what can happen 
> if you lose your Amanda indexes, except that with Amanda you 
> can use native tools to restore everything on your tapes.
> 
> Frank
> 
> 
> -- 
> Frank Smith                                      fsmith AT hoovers DOT com
> Sr. Systems Administrator                       Voice: 512-374-4673
> Hoover's Online                                   Fax: 512-374-4501
>

Hello Frank. That is true, as you point out the DB becomes VERY important in
this type of backup scheme. I believe the way we handled it was to use their
BMR (Bare Metal Recovery) on the backup server (and other critical servers).
I suspect it backs up everything necessary to rebuild the database in case
of failure. Of course this all goes towards the more overhead necessary for
such a scheme.

Regards,
Gordon