Depends on what you are worried about losing. if you mean your media files, the most important thing is that the copy on your TrueNAS system should not be your only copy of them. While it’s unlikely a TrueNAS upgrade will cause a loss of all that data, it’s still possible something will happen that causes you to lose a pool.
Ideally you would want to follow the 3-2-1 rule. Three copies of the data: Two locally (so, your NAS and maybe another copy on another PC or backup drive) and one more off-site. I have my files divided up between a couple high-capacity external hard drives kept elsewhere for my “one”. And occasionally I retrieve those drives and using a file sync program with file verification to update the backup for things I have added or removed from my original copies.
If you mean just your Plex data (libraries, playlists, collections, watch history, etc), you can make a TAR archive of all that, and then copy just that archive somewhere else. That way if you had to remake your Plex system you could just make sure the mount points are all exactly the same and copy the data back to a fresh install essentially. This folder is /usr/local/plexdata-plexpass if you’re using a plain jail install. I believe it’s located someplace slightly different if you’re using the plugin. You want to stop the server process first, and then you can create an archive of the folder by going to the /usr/local directory and running this command:
tar -cvf plexdata-plexpass.tar plexdata-plexpass
This may take several minutes depending on the size of your libraries. Copy the new archive somewhere else (like off your server ideally). Don’t try to just copy the folder as it is to back it up. It will take forever because of the thousands of directory entries it will need to write for all the files themselves. The archive will be small enough to fit on a flash drive (mine’s about 23 GB).
