If you have ever installed Plex on a default installation of Ubuntu, you might have noticed that Ubuntu doesn’t take up the entire disk space for the root (‘/’) partition. This is the reason Plex has the issue described in the title.
This is VERY annoying.
I was really struggling with this issue for a good couple of weeks. When I searched for this issue, none of the results were helpful.
What I had to do: Used a live CD of gparted to increase the space of the partition and then use lvm for the partition to extend into all the new free space.
So, steps below:
Shutdown and boot into GParted live CD/ISO
Startup the GUI and extend the partition you want to expand
Close the GUI and open the GParted Terminal
Enter the LVM manager using: sudo lvm
Extend the default ubuntu vg/ubuntu-lv partition to use all available space: lvextend -l +100%FREE /dev/ubuntu-vg/ubuntu-lv
Now you can exit the LVM manager: exit
Finally, you can resize the system to use the newly sized partition: sudo resize2fs /dev/ubuntu-vg/ubuntu-lv
You can now use df -h and check that the system is using the entire space of the drive and the available partition.
You will now find that the root (‘/’) directory is no longer 99%/100% full and your media can play.