Find the Error
Several messages were logged at different priorities. One is an actual error. Use the journal's priority filter to pick out the error and save it. (Reading the journal needs sudo.)
How it works: the terminal below is a real Linux machine running in your browser. Click it and
type. Tasks tick themselves off as you complete them; questions are answered in the box under each task.
Press Reset any time for a fresh machine. Your password on this machine (for
sudo) is student.
Hints
-p err is the filter for “only the problems”.
-o cat > file saves just the message text.
Solution explanation
sudo journalctl -p err shows only err and more serious entries, so it picks out the DISK FAILURE message (logged by the diskmon tag) while hiding the info and warning ones. The “memory usage is high” message was logged at warning, one level below err.
Show solution
sudo journalctl -b -p warning --no-pager -o cat
sudo journalctl -b -p err -o cat > ~/error.log
cat ~/error.log