As stated above the storage node keeps information about tapes and their contents in a dedicated database. The Rescan task reads information about the content of user-selected tapes and updates the database.
The task can take a long-time so it is only initiated manually. You should select each slot with a tape you want to rescan before the task launch.
Run the Rescan task:
Bear in mind, a tape might keep some backups that were deleted before the tape rescanning. So after the task is completed, all such backups will be recovered in the storage node database and become accessible for data recovery.
At rescanning a tape label should be saved in the storage node database. If a slot, selected for the procedure, contains a tape that still does not have a label, the Rescan task for the tape is paused to perform the Labeling procedure.