From your question, where you say:
Media overwrite option
I assume you mean which should you choose for the option "Overwrite scratch media before overwriting recyclable media contained in the targeted media set".
Imagine you have three types of backup media:
- Media you have already used for a backup, which is protected by the Overwrite Protection Period (protected)
- Media you have already used, which is no longer protected by the Overwrite Protection Period (recyclable)
- Media you haven't used yet (scratch)
When you run a backup, Backup Exec has to decide what media to use. It can't use protected media, so it next has to decide whether to look for recyclable media, or scratch media. If you select the "Overwrite scratch media..." option, it'll look for scratch media first, otherwise it'll look for recyclable media first.
If you are backing up to tape, with this option selected, Backup Exec will tend to use all your tapes. Without it selected, it'll reuse media where possible, before using a new tape.
If you are backing up to disk, with this option selected, Backup Exec will create a new Backup-to-disk file each time it runs a backup. Without it selected Backup Exec will overwrite old files where it can.
That's a bit of a simplification, and you'd be well advised to read chapter 4 of the Backup Exec Administrator's Guide.
Personally I think it's much better to have this option deselected, and I struggle to think of any advantage of selecting it.
