Library Backup Options
Library Backup Options identifies the destinations a music server explicitly supports for copying its music library, such as a USB drive, network storage or a cloud service.
A backup is a recoverable copy. A port or playback connection alone does not establish a backup function.
Library Backup Options — Music Server
Check whether the server can back up to your intended destination and what the copy includes: music files, library information and settings may have different procedures. Also check scheduling, required destination capacity and the documented restore process.
Playing from a NAS or importing music from USB does not mean the server can back up to it. A second internal drive counts as a backup destination only when a separate backup function is provided; an automatically mirrored drive is a redundancy arrangement.
Keep a backup separate enough to survive the failures you need to protect against, and verify restoration. Support for a destination does not prove that backups are enabled, current or complete.