Use Retension media to run the tape in the tape drive from beginning to end at a fast speed so that the tape winds evenly and runs more smoothly past the tape drive heads. Refer to the documentation that came with your tape drive to see how often this utility should be performed.
Retensioning is primarily for Mini Cartridge and quarter-inch cartridges and is not supported on most other types of tape drives.
To retension a tape
Expand the server icon, click Stand-alone Drives, or if the drive is attached to a robotic library, click Robotic Libraries.
Select the drive or slot containing the media you want to retension.
If you want a person or group to be notified when the job completes, on the Properties pane, under Settings, click Notification, and select the options you want.
The job will be submitted as a Run now job, unless you submitted the job on hold. You can monitor the Retension operation from the Job Monitor.
You cannot cancel a Retension operation after it has started; however, you can use Cancel to stop a queued retension operation.