Everytime I had to set up Plex Media Server in Ubuntu I experienced permission problems. I’ve tried many different solutions, some working, most not. I’ve tried using udisks-glue when my drives were formatted as NTFS, but decided that its just much simpler to keep my drives formatted as EXT4 for simplicity.
I finally settled on a solution that works for me. I need to have the ability to remove my media then plug it back in later with Plex not losing any of my metadata for those missing files during their temporary disconnect from my server.
This means I need Plex to have access to my /media/<username> folder. It turns out that by default the Plex user account cannot read this directory even if the permissions on my EXT4 formatted drives have username:plex as a permitted user/group.
The solution that works for me finally turned out to be farily simple. All I needed to do was to give “Other” read permission to my /media/<username> folder with the command:
sudo chmod 775 /media/<username>
This not only allows plex to index my EXT4 formatted drives, but also let me hotplug my external usb drives and plug them in later. Since I only use one user on my server, I also stay logged in to KDE. I also have to set my usb drives to automount when inserted in the Removeable Devices KDE Control Module.