Currently, I have a Plex Media Server on a Win 10 PC with Plex clients on Android, XBox1, and other devices. I would like to move the Plex Media Servier to the low power Raspberry Pi 3 which is always on anyway. The Pi is running Kodi exclusively.
Can I install the Plex Media Server as a background app on the Pi?
Would the Plex for Kodi app provide a server for streaming, or is it a client? Does it require a Plex Pass?
Also, I would like to set up the Pi for NAS.
The answer is yes to all, but that doesn’t mean it is necessarily a good idea.
Kodi, PMS and NAS take up resources on your Pi3, which it does not have plenty of.
I suspect you would have to be careful about the amount of streams and transcoding going on, and then it might work.
Or when you are in a very intensive cliffhanger and someone decides to save his powerpoint presentation on the NAS, it will stutter 
(I have my library shared with friends and multiple consumers in my household. Your situation may be different)
Thanks for the reply. It is usually just me watching movies and TV show on Kodi, and listening to music on Plex (not at the same time). I don’t think sharing resources will be a problem. The NAS would be used for uploading new media for Plex.
