Testing for Bad Media

Testing for Bad Media

Even the best media can go bad over time. Symptoms are:

Data appears to load onto the tape correctly, but the backup fails verification tests. (This is a good reason to always verify backups immediately after you make them.)
Another tape is then able to back up the data successfully and pass verification tests.
Data retrieved from the tape is corrupted, while the same data loaded onto a different tape is retrieved without problems.
The backup media device driver (such as the SCSI tape driver) displays errors on the system console when trying to access the tape.
You are unable to write information onto the tape.

If errors occur when you try to write information on a tape, make sure the tape is not simply write-protected. Be sure you are using the correct length and density tape for your drive.

Make sure that your drive is clean and that tape heads are aligned properly. It is especially important to check tape head alignment if a series of formerly good tapes suddenly appear to go bad.

Once you are satisfied that a tape is bad, mark it as a bad tape and discard it. Be sure to mark it "bad" to prevent someone else from accidentally using it.