I installed Plex Media Server on Arch recently and added my media library which is located on 2 separate HDDs. My Arch install is on an SSD and I had ~30GB free on my /home partition and more than 5GB free on / Partition.
Within 30 minutes, I started getting messages about my / directory having less than 1GB free space. I tried to find the database file to move it to another HDD but unlike debian based distros, NOTHING is installed where it should be and NO documentation on where it is located seems to exist.
Help! This is another reason I am wanting to drop Arch and go back to something Debian based.
Sounds like somethings wrong there, why is your plex db so large? I have several TBs of content on my disk array and plex's db/index is only 1.8GB.
Scanning for extra large dirs should point you to where its vomiting data to.
I think there are issues with the Plex package for Arch, It isn't officially support on that distro so I am not sure where the package came from. But if you chech the Arch forums you aren't the only one having issues with it.
Ever consider switching to a free home media server such as emby (mediabrowser)? Coming from someone who use to use Plex, there are no compromises, well not at least for my use. Sorry I don't any any information that could help you on your current problem.
Does that have a mobile app?