SOLVED: Change media library paths

[TheDreadPirate]

You need to have the new folder in your library, even if it is currently empty, ahead of time if you want a clean cut over. But if this is for a whole you will have to think ahead a little.

You will have create the folder you are going to mount the hard drive to NOW and add it to your docker config, then add this folder to your library.

Stop Jellyfin, change where the hard drive is mounted, start Jellyfin. It SHOULD cut over cleanly and rescan everything but preserve metadata and watch status.

You can always backup /config just in case.