Paul Bijnens wrote:

Toralf Lund wrote:

Other possible error sources that I think I have eliminated:

  1. tar version issues - since gzip complains even if I just uncopress
     and send the data to /dev/null, or use the -t option.
  2. Network transfer issues. I get errors even with server
     compression, and I'm assuming gzip would produce consistent output
     even if input data were garbled  due to network problems.
  3. Problems with a specific amanda version. I've tried 2.4.4p1 and
     2.4.4p3. Results are the same.
  4. Problems with a special disk. I've tested more than one, as target
     for "file" dumps as well as holding disk.

5. Hardware errors, e.g. in bad RAM (on a computer without ECC), or
disk controller, or cables.

If one single bit is flipped, then gzip produces complete garbage from
that point on.

Maybe you're only seeing it in such large backups with gzip, but it happens (less often) in other cases too.

Any tools available to test the hardware?

- Toralf