A rule of thumb concerning bad blocks on SCSI drives is:
Since SCSI usually allocates about 2% of the area for mapping bad block automatically, if you get more that 5% more allocated bad blocks it's time for a new drive.
The Device name may also be omniscsi.gevice if you havre the GURU Rom for GVP controllers.
I highly recommend buying this ROM upgrade wile you still can. Schatztruhe doesn't distribute or support it any longer but places such as Sortware Hut probably still have it.