One of my servers went belly-up. It is always unfortunate when you are confronted with a failing server. If you ever get messages like this, the hard disk on which your Operating System is installed, is probably K.I.A.. In the end I did a hard reset and was greeted with busybox (which was expected). Just wanted to share the kind of 'weird' messages you can see when you have I/O errors due to a failing drive (in this case it was a USB stick, not a HDD or SSD).
:user@hostname:~$ ssh cyberdyneinc.net.sukar Linux sukar 4.19.0-14-amd64 #1 SMP Debian 4.19.171-2 (2021-01-30) x86_64 The programs included with the Debian GNU/Linux system are free software; the exact distribution terms for each program are described in the individual files in /usr/share/doc/*/copyright. Debian GNU/Linux comes with ABSOLUTELY NO WARRANTY, to the extent permitted by applicable law. You have new mail. Last login: Tue Jul 27 13:03:33 2021 from 10.83.1.239 -bash: /usr/bin/id: Input/output error -bash: [: : integer expression expected -bash: /etc/bash_completion.d/docker: Input/output error -bash: /etc/bash_completion.d/docker: Input/output error user@sukar:~$ sudo -i [sudo] password for user: -bash: /usr/bin/id: Input/output error -bash: [: : integer expression expected -bash: /etc/bash_completion.d/docker: Input/output error root@sukar:~# journalctl -f Bus error root@sukar:~# df -h -bash: /bin/df: Input/output error root@sukar:~# reboot -bash: reboot: command not found