Temperature Threshold Minus 10 Degrees using RPN Expression

[TempGrapher]

Hi I am currently in the process of trying to setup some thresholds to receive alerts when a temperature of a particular probe is 10 degrees below the hardware threshold. I am trying to set this below the threshold by 10 degrees because if it hits the threshold the server powers down to avoid hardware failure. I figured that I could create a template that would apply this to all the graphs so that I wouldn't have to do this by hand. I have two datasources available: |ds:Threshold|, |ds:Temp|. What I did was created an expression "|ds:Threshold|,100,- " (NOTE: I am subtracting 100 to verify that the expression is working for the time being. ) I received an email stating that the threshold has been breached (WOO HOO!) HOWEVER!, when I looked at the email it shows that the current temperature probe of the server is -86, which it is actually 14, and that it passed a threshold of 0, which this particular server probe has a threshold of 38. I am not sure why it is subracting the 100 from the temperature instead of the threshold. I have attached a screen shot to see how i setup the threshold. I would have expected the email to stating that the temperature went above a threshold of -62 with a temperature of 14 since it should (or so i thought) have subracted the 100 from the threshold and not the temperature of the probe. If more information is required please let me know! Just another note, the reason for me doing this is so that I do not have to go through hundreds of thresholds and set the max value of each one because they vary from graph to graph so unless anyone else has an idea of how to set the max threshold minus 10 degrees from the SNMPwalk i would be very interested in that also.

[TempGrapher]

I actually just realized that this is definetly not working like i was expecting.. I had the exact value drop down statically set to 38 degrees for the "HIGH Threshold". Does anyone know if its possible to set the High Threshold based off of the High threshold it receives when cacti does the snmp walk? The graphs show the Threshold and in the XML for the mib walk it has the following:

<hpHealthTempThresh>
<name>Threshold at which the temperature is considered a failure</name>
<method>walk</method>
<source>value</source>
<direction>output</direction>
<oid>.1.3.6.1.4.1.232.6.2.6.8.1.5</oid>
</hpHealthTempThresh>


So it is polling the threshold value in the graph.. How would I be able to take this value from the graph cacti created and subtract 10 degrees? I have attached a graph that Cacti Created from the mib walk.

[TempGrapher]

Anyone have any thoughts on this?

[TempGrapher]

This is another thing worth noting. I see that Cacti does display the current threshold of the device it is monitoring under the"Thresholds" tab (See Screen Shot). So there must be some kind of variable that it uses. Is there a way of editing the thold files to use this variable and subtract 10 degrees and have that used in "High Threshold" Field?

[TempGrapher]

No one has any ideas on this??