Because Aurender music servers (with the exceptions of ACS and A30 models) are not content creators, it is assumed that an Aurender music server is not a "master" copy of one's music library and it instead acts as a backup of music files that already exist on another storage device. Therefore an automated "backup" feature has not been implemented with Aurender music servers at this time.
However, you can manually create a copy of your Aurender music library database (playlists, ratings, etc.) and the music files on the internal storage drive of the Aurender by connecting to the Aurender from a Mac or PC as a shared folder on the local area network. Please see the below links for detailed instructions on backing up from either a Mac or PC.