> Why are you low-level formatting SCSI drives? This is usually only needed
> if you want to change block sizes and other low-level things. In future,
> refrain, low-level formatting will cause you many more headaches than it 
> will solve.

Sometimes, low-level formatting will cure soft read errors.  Some drives
perform pessimistic media certification during format and will remap poor
sectors then, but won't remap those sectors during normal operation until
they fail more than a couple of passes through the error recovery algorithm.