DLTSage Errors with the Tape Library Option

If Arcserve Backup detects a problem with a tape drive, there are three mechanisms Arcserve Backup uses to cure tape drive errors:

Drive Error Prevention

Before performing a backup job, Arcserve Backup evaluates the tape drive’s health. If DLTSage detects a problem with a tape drive, Arcserve Backup performs the following analyses and actions:

• If another tape drive is available (empty) Arcserve Backup moves the tape to the next available tape drive and runs the backup job.
• If there are no available drives, Arcserve Backup moves the tape to a tape drive that is not locked, and runs the backup job.
• If all other drives are locked, Arcserve Backup runs the backup job in the current tape drive.

Drive Usage Balancing

Arcserve Backup balances tape drive usage by rotating the usage of tapes evenly between all tape drives in your library. When Arcserve Backup starts a backup job, it detects the last drive used and uses the next available drive in the library.

To minimize the movement of tapes from tape drive to tape drive, Arcserve Backup performs the following analyses and actions:

• If the media targeted for the job is loaded, allow it to remain in its current drive and run the backup job.
• If the media targeted for the job is not loaded, identify the last used drive and load the tape into the next available, empty drive, and then run the backup job.

Uninterrupted Drive Cleaning

A contaminated tape drive condition is usually discovered when you are running a backup job. A significant number of tape drive and media errors can be remedied by cleaning the tape drive.

For Arcserve Backup to perform uninterrupted drive cleaning, you must have a cleaning tape installed in the tape cleaning slot specified during setup, and specified a cleaning schedule. If you did not specify a cleaning schedule, Arcserve Backup defaults to a 100 hour period between scheduled tape cleaning operations.

If Arcserve Backup detects a contaminated tape drive condition during a backup job, and a cleaning slot is configured, Arcserve Backup automatically performs the following analyses and actions:

• If Arcserve Backup detects a write error during a backup, and the symptoms relate to a contaminated tape drive or media, Arcserve Backup makes a second attempt to write to the tape drive.
• If the second write attempt fails, Arcserve Backup cleans the tape drive if one or more of the following conditions exist:
• The tape drive was never previously cleaned.
• DLTSage detected the need to clean the tape drive and drive usage exceeds one fourth of the scheduled cleaning.
• Tape drive usage exceeds one third of the cleaning.
• The user specified ForceClean the tape drive.

If Arcserve Backup determines that a tape drive must be cleaned to continue a job, the following actions take place:

• Arcserve Backup pauses the job.
• The library returns the tape to its home slot and locks the tape drive.
• Arcserve Backup directs the cleaning operation.
• The library reloads the tape into the cleaned drive and aligns the tape with the buffer.
• Arcserve Backup resumes the job.

Note: These mechanisms run automatically upon error detection. No user intervention is required. After Arcserve Backup cures the error, the backup job continues. For more information about automated error resolution, see the Tape Library Option Guide.