nst0 attached to a raid card gives lots of errors

Hello to everyone on this list,

	I have a tape drive that is exhibiting very strange behaviour.  It
will work fine once and then throw i/o errors and stop the backup from
working.  When the st driver is loaded I get these messages in the logs:

Aug 28 04:04:10 pronto kernel: Attached scsi tape st0 at scsi5, channel 4,
id 3, lun 0
Aug 28 04:04:10 pronto kernel: st0: Block limits 1 - 16777215 bytes.

Aug 30 04:03:22 pronto kernel: Attached scsi tape st0 at scsi5, channel 4,
id 3, lun 0
Aug 30 04:03:27 pronto kernel: st0: Block limits 1 - 16777215 bytes.
Aug 30 04:07:21 pronto kernel: st0: Error 250400f1 (sugg. bt 0x20, driver bt
0x5, host bt 0x4).
Aug 30 04:07:21 pronto kernel: st0: Error on write filemark.
Aug 30 04:09:27 pronto kernel: st0: Error 250400f1 (sugg. bt 0x20, driver bt
0x5, host bt 0x4).
Aug 30 04:10:33 pronto kernel: st0: Error 250400f1 (sugg. bt 0x20, driver bt
0x5, host bt 0x4).
Aug 30 04:10:33 pronto kernel: st0: Error on write filemark.

As you can see sometimes it loads fine and other it does not.

I am left wondering if attaching a tape drive to an old raid card (it
reports itself as megaraid) was a good idea and if any hardware minded
people on this list would know if it would be better just using a standard
scsi controller from either 3ware or Adaptec?

The other strange things I see are if I do mt -f /dev/nst0 status and a tape
is in the drive, it will report the status.  If I do that and no tape is in
the drive it will sit there until a tape is inserted and after 2 tries at
running the command with I/O errors, it will again report the status
correctly and continue to do so as long as there is a tape in the drive.

These problems mean that sometimes my backup works other times it doesn't.

Any suggestions would be greatly appreciated.

Cheers Geoff