I assume Volumio stores all the information about the music library in some sort of database file.
Where is this file(s) stored so that I can back it up?
Volumio seems to take forever to index my NAS and I need to re-flash a later version of Volumio and don’t want to have to re-index the NAS from scratch.
There was a discussion about this a while ago, not sure if anything resulted from it.
It would be a nice idea for a plugin though, being able to make a backup of music directories, including the settings for the corresponding NAS/USB drives.
Any volunteers? 
Is there any config-file where you can point the database to an externial usb media device (like minidlna) ?
No, there is no current provision within Volumio to achieve your aims. It would be much easier to achieve from within a plugin (assuming that someone is willing to write one).
Thank you! Good to know, because Volumio with minidlna, Usb hd, bubbleupnp (Android Tablet) is working flawless and I see no advantage to try mpd and maybe mpdroid.
So is the library database stored in a file that can be copied for backup?
Did you ever find the database file location?
I’m having trouble with Volumio “clearing” the my Music file instead of updating. It occurs when Volumio hasn’t connected to my NAS even though the NAS is running and I’ve just copied new music to it. It takes about 8 hours to restore the files within My Music and I’d very much like to back the file up before I attempt another update.
BTW the back up Plugin didn’t restore the My Music register when I tried it last time it Zeroed.
That’s the best outcome! When you find a combo (Volumio, minidlna, USB, and BubbleUPnP) that’s working flawlessly, stick with it. No need to mess with a stable system just to try out mpd/mpdroid.
8 months on wondering if anyone has found a solution to the library database cock up. Doing yet another eon of a rescan as I type.
Find it hard to believe that i cant boot the system without having to “teach” it where my NAS is stored every time else I lose my library when i update it.
Back the file up rather than delete it ?
Thanks, ive not SSH’d in for a while. I’ll have a go at backing it up. Certainly would be better thank starting from nought (I have 150,000odd tracks)
Cheers,
Neill