>>>>> On Thu, 02 Aug 2007 13:49:10 +0200, Carsten Ralle said:
> 
> I've been struggling with Bacula for a single backup installation for
> almost 4 months now. Although installation and configuration are well
> documented I'm still confused by two problems we can't get solved:
> 
> 1. Even with brand new tapes, on two different tape drives, using
> continuous cleaning cycles, the tapes that used to store between 11.5
> and 13 GB uncompressed data on a windows machine only take about 8 GB
> using bacula (same drive, same tapes).
> 
> Following the advice to switch off software compression when hardware
> compression is enabled, we run tests with following results (always the
> same fileset of 23 GB uncompressed data)
> 
> hw-compress  sw-compress  spool size  data/tape  total # of tapes used
>     on          on           14 GB       8.2 GB          1.7
>     on          off          23 GB      12.9 GB          1.8
> 
> so we use the installation with both sw and hw compression turned on, as
> it gives us better performance and less tapes/backup.
> 
> Why is it impossible to store more then 8 GB on a 12/24GB tape. Again:
> we ran the tests on multiple different drives (HP15xx and Sony
> DDS3-drives).

The problem is that DDS hw compression is not very good.  In particular, when
you use sw compression as well, the data written to tape actually gets
expanded by the hw compression so your 8.2 GB of input gets written as 12 GB
on the tape!

Have you tried with hw compression off and sw compression on?


> 2. Up to now a verify at level "VolumeToCatalog" always (!) brings up at
> least one error of the type "Error: block.c:317 Volume data error at
> 3:2817! Block checksum mismatch in block=2817 len=64512: calc=8fe728a4
> blk=bd217fe3" in the middle of the tape.
> After that bacula dupms the whole remaining file list into an email
> message of about 30MB in size.
> 
> - Is there any way to make Bacula stop to send the file list while keep
> on sending email notifications ?

If your mailcommand uses bsmtp, then you can set the -l option.


> - How can it be, that a single error renders the whole tape of a backup
> useless ? Why does bacula not continue to verify the other 80% of a
> backup and tells something like "block error while reading ..., missing
> files ...." ?

Hmm, I thought it would continue.  Are there any other errors after the
checksum mismatch?  Can you try restarting the bacula-sd with the -p option?

__Martin

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