[ILUG] dump failure on RH6.1

[Lars Hecking]

 Backups on a local RedHat 6.1 box are failing mysteriously:

  DUMP: Date of this level 0 dump: Tue Jun  6 22:20:28 2000
  DUMP: Date of last level 0 dump: the epoch
  DUMP: Dumping /dev/hda6 (/export/home) to /dev/nrmt0h on host backuphost
  DUMP: mapping (Pass I) [regular files]
  DUMP: mapping (Pass II) [directories]
  DUMP: estimated 1662846 tape blocks on 0.02 tape(s).
  DUMP: Volume 1 started at: Tue Jun  6 22:20:47 2000
  DUMP: dumping (Pass III) [directories]
  DUMP: dumping (Pass IV) [regular files]
  DUMP: 9.91% done, finished in 0:45
  DUMP: 19.59% done, finished in 0:41
  DUMP: 29.29% done, finished in 0:36
  DUMP: 39.04% done, finished in 0:31
  DUMP: 48.86% done, finished in 0:26
  DUMP: 58.32% done, finished in 0:21
  DUMP: bread: lseek fails
  DUMP: bread: lseek fails
  DUMP: short read error from /dev/hda6: [block -45113312]: count=4096, got=0
  DUMP: bread: lseek2 fails!
  DUMP: short read error from /dev/hda6: [sector -45113312]: count=512, got=0
  DUMP: bread: lseek2 fails!
[last two lines repeat a couple of hundred times]
  DUMP: short read error from /dev/hda6: [block -837093952]: count=4096, got=0
  DUMP: More than 32 block read errors from 134576624
  DUMP: This is an unrecoverable error.
  DUMP: fopen on /dev/tty fails: Device not configured
  DUMP: The ENTIRE dump is aborted.

 The filesystem to be backed up:

Filesystem           1k-blocks      Used Available Use% Mounted on
/dev/hda6              4269316   1996068   2056376  49% /export/home

 dump is the the version that comes with RH6.1, dump-0.4b4-11.

 I find it strange in particular that the backup proceeds nicely
 until about 60% are done, but craps out after that (it's also extremely
 slow; around 300kB/s over a 100Mbit/s ethernet is nothing to boast of).

 Has anyone seen this before? Any ideas?