See here:
First you want to stop the server process on both the Plex servers (so it’s not making changes to the data while you are transferring it).
The location of the plexdata-plexpass folder is slightly different on the plug-in install of Plex. I can’t find the post right now, but someone else with a similar question mentioned were they found it in a post somewhere. But that’s the name of the folder.
Make the tar archive from the directory as mentioned in that post.
You need to use the shell on the main TrueNAS system to copy the archive to the new jail (since you’re moving a file between two separate jails).
cd /mnt/JAILDRIVE/iocage/jails/OLDPLEXJAIL/LOCATION/OF/OLD/SERVERINFO
cp plexdata-plexpass.tar /mnt/JAILDRIVE/iocage/jails/NEWPLEXJAIL/root/usr/local
and expand the archive back into the normal directory:
tar -xvf plexdata-plexpass.tar
Make sure permissions are correct:
chown -R plex:plex plexdata-plexpass
And then restart the Plex server on the new jail:
service plexmediaserver_plexpass start
Since your mount points are all the same, the server should find all your media in the same places. You may want to sign out the server from your Plex account and sign back in to refresh the SSL cert stuff since you copied it from another Plex server. But that should be it. Obviously this works best when both Plex servers are on the same server version, but I assume Plex will just update the database and such as needed if the previous server was a bit behind, like with any PMS upgrade.
