Is anyone else experiencing a problem with dump?

On my sparc I'm running a relatively -current kernel due to some scsi issues
that PK took care of; and a 1.4 userland... The symptoms exhibited themselves
with a 1.3H userland as well however.

The problem is that after writing 100-1000MB, dump just 'stops' doing anything.
I saw this happen while doing a 'dump|restore' from one filesystem onto another
and last night while doing a 'dump | dd' onto a tapedrive...

 # dump 0f - /usr/local/cd | dd of=/dev/rst1 bs=64k
  DUMP: Date of this level 0 dump: Tue Jun 22 21:53:39 1999
  DUMP: Date of last level 0 dump: the epoch
  DUMP: Dumping /dev/rccd0a (/usr/local/cd) to standard output
  DUMP: Label: none
  DUMP: mapping (Pass I) [regular files]
  DUMP: mapping (Pass II) [directories]
  DUMP: estimated 16265359 tape blocks.
  DUMP: Volume 1 started at: Tue Jun 22 21:58:12 1999
  DUMP: dumping (Pass III) [directories]
  DUMP: dumping (Pass IV) [regular files]
  DUMP: 1.69% done, finished in 4:51
  DUMP: 3.43% done, finished in 4:41
  DUMP: 5.13% done, finished in 4:37
   .....


That was how I left it last night when I went to bed. This morning, it hadn't
changed at all... 'systat iostat' showed no disk activity whatsoever.

a "kill -INFO" then produced:

5.19% done at 22 KB/s, finished in 187:05
5.19% done at 22 KB/s, finished in 188:05

finally, interrupting the dump produces:

^C^?0+212257 records in
0+212257 records out
864552960 bytes transferred in 37382 secs (23127 bytes/sec)
  DUMP: Interrupt received.
  DUMP: Do you want to abort dump?: ("yes" or "no")

which is normal.

Same thing when not going through 'dd':

 # dump 0Bf 25000000 /dev/rst1 /usr/local/cd
  DUMP: Date of this level 0 dump: Wed Jun 23 08:26:33 1999
  DUMP: Date of last level 0 dump: the epoch
  DUMP: Dumping /dev/rccd0a (/usr/local/cd) to /dev/rst1
  DUMP: Label: none
  DUMP: mapping (Pass I) [regular files]
  DUMP: mapping (Pass II) [directories]
  DUMP: estimated 16265362 tape blocks on 0.65 tape(s).
  DUMP: Volume 1 started at: Wed Jun 23 08:31:08 1999
  DUMP: dumping (Pass III) [directories]
  DUMP: dumping (Pass IV) [regular files]
  DUMP: 2.17% done, finished in 3:45
  DUMP: 4.45% done, finished in 3:34
  DUMP: 6.76% done, finished in 3:26
	....				<----- at this point I confirmed no I/O
^?  DUMP: Interrupt received.
  DUMP: Do you want to abort dump?: ("yes" or "no") yes
  DUMP: The ENTIRE dump is aborted.


I know the problem is not with the tapedrive because I can 'tar cf - | dd' onto
it just fine.  Plus the problem occurs with 'dump|restore' from one filesystem
onto another...

The tape drive in case anyone cares is a DLT-4000...

Is anyone else seeing this? I wanted to find out before doing a send-pr because
it could be some sort of localized weirdness..