Accessing my Plex database on RN214

You'll find the folder in /.apps of the data volume (which is hidden).

From windows you can access the entire data volume to a drive letter using NAS admin credentials.  From CMD you can map it to drive letter T by doing this:

net use * /delete /y
net use t: \\nas-ip-address\data /user:admin nas-admin-password

using the real IP address and admin password of course.  You do need be careful on the typing - particularly the slash directions.

From there you can access T:\.apps\plexmediaserver-annapurna.  On an x86 ReadyNAS the location is just plexmediaserver.  The media library itself is in T:\apps\plexmediaserver-annapurna\MediaLibrary\plex media server

There are a lot of files, and the path names get fairly long.  It can be difficult to copy them all (file permissions can get in the way).  Another approach is to use ssh.  If you access the NAS using ssh, you can zip the entire folder using something like this

# cd /apps/plexmediaserver-annapurna
# zip -r MediaLibrary.zip MediaLibrary
# chown MediaLibrary.zip admin
# chgrp MediaLibrary.zip admin

If you do use ssh, use "root" as the username with the NAS admin password.  The last two commands change the zip file ownership from root to admin (also changing the group).  They just ensure that you can copy (and delete) the zip from windows later on.  You can unzip on the other NAS using unzip (ssh), or by mapping the drive letter in Windows as described above, and using a zip utility like 7-zip.