Here is a simple plist for plex media server to keep it up and running on osx. Download the zip Prior to install change the __USERNAME__ string in the plist with your username. Open terminal then enter these commands:

sudo su
# Change directory to the com.plex.pms.plist-master
chmod +x install.bash
./install.bash

If you need to unload the plist for any reason open terminal then enter these commands:

sudo su
cd /Library/LaunchDaemons
launchctl unload com.plex.pms.plist