Monit 5.27.0 appears to have introduced a problem on FreeBSD 11.4:
# monit stop apache /usr/local/etc/monitrc:135: The CPU I/O wait usage statistics is not available on this system '60'
The ‘offending’ bit of monitrc (I changed the hostname to *.example.com):
check system webserver.example.com if loadavg (1min) > 15 for 3 cycles then alert if loadavg (5min) > 12 for 3 cycles then alert if memory usage > 90% then alert if cpu usage (user) > 80% then alert if cpu usage (system) > 60% then alert if cpu usage (wait) > 50% then alert
The changelog indicates lot of changes regarding CPU statistics so I suspect a bug was introduced. If I revert back to 5.26.0 it works as expected.