Just a note that I have experienced a similar problem, but with
Redhat and Mandrake rather than Debian Linux.  The dump format
is GNU tar with gzip compressed on the client side, written to
a large holding disk then flushed to tape.  The archives on
holding disk verify OK, but the problem is retrieving them
from tape.  So I suspect it is a hardware, SCSI cabling or kernel
problem when writing to tape.  It's mostly dumps > 8-10GBs that
have problems, and then only about 1 out of 3 dumps.

However, the dumps done without using gzip have had no problems
during restores, and I've done a lot more of those than
restores of the gzip'd dumps, which I only used on clients
with fast CPUs which don't run batch jobs at night.  I've turned
on hardware compression and turned off client side compression as
an acceptable workaround.  Still trying to find a way
to resurrect corrupt gzip tar archives.

Also Sprach Eric Siegerman:

> On Tue, Jul 15, 2003 at 12:10:27PM -0400, Kurt Yoder wrote:
> > However, I
> > was able to duplicate the problem simply by gzipping a big file to
> > my ATA/IDE holding disk. So I'm certain it's not a scsi problem.
> 
> Is it repeatable?  I.e. if you gzip the *same* file five times,
> do you get the same error five times, at the same location?  Or
> do you get five different errors?  Or maybe a mix of errors and
> successes?
> 
> The former would point to a bug in gzip; the latter to hardware
> problems of some sort (or kernel, but I'd bet on the hardware).
> 
> Try that test on your freshly installed Debian box, that you say
> works fine.  Then install (but don't use) Amanda and try it
> again.
> 
> Divide and conquer :-)
> 
> --
> 
> |  | /\
> |-_|/  >   Eric Siegerman, Toronto, Ont.        erics AT telepres DOT com
> |  |  /
> When I came back around from the dark side, there in front of me would
> be the landing area where the crew was, and the Earth, all in the view
> of my window. I couldn't help but think that there in front of me was
> all of humanity, except me.
>       - Michael Collins, Apollo 11 Command Module Pilot
> 

----
C. Chan <c-chan AT uchicago DOT edu >
GPG Public Key registered at pgp.mit.edu