We are using the predefined sensor „Dell System Health“. One of the sensors (Power Unit Status) says NULL from the SNMP-query which is made in the background. This is interpreted as „red“ which makes the whole sensor always red.
We were looking in the iDrac management interface what the trouble could be: nothing. All flags are green there.
The trouble _could_ be that we only have one power supply, not two.
We would like to see the sensor green despite of this Power Unit Status. We are not able to kick out this check because we could not find the definitions of this sensor-type. We did not want to change the lookup values for all Dell Servers in C:\Program Files (x86)\PRTG Network Monitor\lookups\prtg.standardlookups.dell.dellstatus.ovl
The solution was to this to this special _channel_ and edit the channel settings – Spike Filter – Enable spike filter – Spike Filter Max = 0 – Spike Filter Mix = 0
The result is that the result from the sensor is not interpreted and not judged as trouble be PRTG. All other important values get checked, which is important for us.