We are using PRTG to monitor our NetApp but are having trouble that PRTG Displays negative numbers for larger values which makes the monitoring quite useless.

http://db.tt/nL9oMGc

Article Comments

This seems to be an overflow. This shouldn't occur if you use 64-bit counters (SNMP v2c).


Nov, 2010 - Permalink

Hi, You are probably right about the overflow. I tried using another tool for monitoring and got the same negative value, it seems like its the snmp definition from NetApp that is "wrong" somehow. Later on i found that other people with netapp - on their forums had same troubles.

But I found a workaround, by using custom sensors and using a batch-file, a command linke snmp-get, and a pythonscript.... And adding 4294967296 if the number is negative.

Its manageble defining these custom sensors for just two sensors i need to monitor, but i really would need to monitor about 10-30 sensors to get a good overview of the disk usage.

It would be really nice if one could do a bit math directly in the sensors, since i dont think its possible to always have right values from snmp.... And some of the result values from my netapp are divided in two different snmp-fields that eventually needs to be added together to make sens.


Nov, 2010 - Permalink

Create a new SNMP Custom sensor, and select value type "Gauge - signed"


Feb, 2012 - Permalink