I reached that dreaded moment where our perforce server hit its maximum limit.
Even when trying to obliterate some directories from our depot, I was getting hit with the reply:
The filesystem ‘P4ROOT’ has only 2G free, but the server configuration requires at least 2G available.
P4Configure to change this file size requirement did not work for P4Root.
What I ended up having to do was log on as the root user of my digital ocean hosted linux server, navigate up to the home directory by doing cd .. and then navigate into the perforce folder and manually delete one of the smaller projects from the archives folder.
After doing this, I was able to obliterate a larger project and verify the new space on the p4 server with the p4diskspace command.
At some point later I will need to look into setting up perforce to delete older archived versions of files.