I have a 7042P-8R and one of the four drives always fail on channel B on the backplane, but channel A is fine. It doesn't matter which cable is connected to the SCSI/RAID controller, but follows channel B on the backplane. Is channel B bad?
This could be caused by a few different reasons: (1) you may need to change the SCSI cable, (2) you may need to change the SCSI backplane, or (3) you may need to update the firmware on the SCSI hard drives.