So, I think that #NixOS VM I had is dead. When it ran out of space, the /etc/passwd got yeeted somehow. I can triage it enough to get my gitea database and files off of it, but i'll probably move distros.
I didn't have BTRFS compression on. (Once I applied it, it saved nearly 2/3rd of the drive's space, so it would've been able to continue for a long time)
I didn't have garbage collection on, so the systems would just keep piling up.
I didn't check on it to make sure it wasn't filling up.
I'm debating what I could do in the future. Maybe I could make a daemon that checks the disk space, and when it gets below 2%, maybe initiate a shutdown and force the user into a single user mode to fix the issue? It's not like these services need to be up 24/7, so downtime isn't an issue.
I'll probably move the server over to Slackware or Devuan though (Or maybe even a BSD), so I don't think i'll see this problem as much.