Is this the DAT tape drive?  It write a load of files out to the tape before
this happens and it has happened on two seperate tapes 90m and 120m.

I'm not sure the capacity of the tape drive, it may only be a 1Gig (does
this happen when you run out of tape?)

tar (child): only wrote 2048 of 2508 bytes to /dev/st0
Aug 30 18:48:30 webmail /netbsd: st0(ncr0:4:0):  Check Condition on CDB:
0x08 00
 00 08 00 00
Aug 30 18:48:31 webmail /netbsd:     SENSE KEY:  Blank Check
Aug 30 18:48:31 webmail /netbsd:    INFO FIELD:  2048
Aug 30 18:48:31 webmail /netbsd:      ASC/ASCQ:  End-Of-Data Detected
Aug 30 18:48:31 webmail /netbsd:
Aug 30 18:48:31 webmail /netbsd: st0(ncr0:4:0):  Check Condition on CDB:
0x08 00
 00 08 00 00
Aug 30 18:48:31 webmail /netbsd:     SENSE KEY:  Blank Check
Aug 30 18:48:31 webmail /netbsd:    INFO FIELD:  2048
Aug 30 18:48:31 webmail /netbsd:      ASC/ASCQ:  End-Of-Data Detected
Aug 30 18:48:31 webmail /netbsd: