Hello,
I know this does not help you very much, but I would say usually this is not a Data Protector problem.
Something wrong with the SAN, or the driver, or the possibly the drive or library ?
You could download LTT (Library Test Tools) to the server where you are running `devbra -dev`and see if that sees the Serial Numbers of all the drives or not.
Update the driver, update the drive/library firmware perhaps ? Look at the SAN logs ?
Best regards, Stewart