broken node

Hello all, I am running into a seemingly unique issue where my cluster will splitbrain on its own. This happened on last reboot and seemed to start because the /etc/hosts file no longer defined the correct member ips and host names. I fixed that and the cluster will work for about 3 minutes...

Long story short: ssd is full, can boot server w some errors on boot, can login root, but can not run any qm commands even qm list - i/o error what to do? If I add some drive does it help? How to add drive without web interface? May I just move VMs manually to new hdd, format and setup...