Preparing tapes is a requirement for archiving to tape. Preparing the tape overwrites all existing data and reformats the tape for archiving with Unitrends. Tapes can be prepared automatically or manually. To automatically prepare tapes, set use_unlabeled_tapes to True (Step 7 of To configure a tape drive). All tapes within the selected range, are prepared before the first archive job. If this field is set to False, archiving does not write or prepare data to a tape that have not been prepared. Setting the field to False allows for greater protection of archive media containing non-Unitrends backups at the cost of having to manually prepare tapes before they can be used for archiving.
The use_unlabled_tapes setting has no impact on tapes containing Unitrends backups. Use retention settings to prevent archive jobs from overwriting data on these tapes. For instructions on preparing tapes manually, see To prepare archive tapes.
If your autoloader does not read tape barcodes, and you have a combination of tapes with Unitrends and non-Unitrends data, it is recommended that you set use_unlabeled_tapes to False to thoroughly protect your non-Unitrends data.
When an autoloader has a tape in the drive, it recognizes the slot from which that tape was loaded. Some autoloaders forget the tapes slot assignment if the autoloader is turned off with a tape still in the drive, or if there is an unexpected loss of power. An unload operation may then fail to return the tape to its proper slot, which may cause an incorrect assignment of the tape during archiving. For example, if you have 10 slots, and you set your Unitrends archiving range to 1-8; the sudden loss of power could cause slot 9 to placed in slot 4, and could result in the tape from slot 9 (now slot 4) being prepared and written over.
If set to False, you must prepare tapes before archiving as described in To prepare archive tapes.