Munin

Error for checks involving the word 'root'

You may see errors in /var/log/munin/munin-graph.log of the form:

... : opening '/var/lib/munin/--g.rrd': No such file or directory

This sometimes occurs because the particular monitor returns a category of "root", which is a reserved word in munin. To fix this, you need to patch a few munin files, as described here: http://munin-monitoring.org/ticket/794.

I noticed this issue for cpubyuser, and lvm_myhost (since I had an lvm volume called "root").

Very low warn threshold for sensors

This happens because munin treats the sensor hyst value as the warning value when output looks like:

 GPU Temp:     +62.0°C  (high = +100.0°C, hyst =  +3.0°C)
                        (crit = +105.0°C, hyst =  +2.0°C)
                        (emerg = +110.0°C, hyst = +10.0°C)

A simple workaround is just to ignore warn values less than 10C in /etc/munin/plugins/sensors_temp:temp_threshold with:

   if (defined($min) and $min < 10) {
     $min = $max;
   }