I'm trying to create a performance graph to show HTTP connections per second on our F5 LTM appliances. The OID (188.8.131.52.4.1.33184.108.40.206.2.1.56), reports the running total of HTTP requests. The actual value means very little to me since there is no defined time. The running total probably began last time the appliance was rebooted.
I need the ability to get the delta between value of the current poll and the value of the previous poll and then divide by the interval. This would give me the number of requests per interval. I can then use a Transform to convert to requests per second. For example:
Poll 1 (at 11:00am): 220.127.116.11.4.1.3318.104.22.168.2.1.56 --> 1230000000
Poll 2:(at 11:02am): 22.214.171.124.4.1.33126.96.36.199.2.1.56 --> 1230360000
Delta = 1230360000 - 1230000000 = 360000 requests
360000 requests / 2 minutes = 180000 requests per minute or 3000 requests per second
When I added the poller and checked the data, it showed the actual raw values from my F5 appliances. I thought setting the MIB value type to Counter would report the delta between the values but it doesn't. I played around with the different settings but couldn't find any option that would help. In the documentation, there is a speedometer example under the Counter section:
As an example, a Counter value corresponds to the value, in miles, returned by a car odometer. To produce results equivalent to a speedometer‑type rate poller, create a clock poller that returns another Counter value, in hours, and then create a poller transform that divides the result of an odometer poller by the result of the clock poller.
Applying that example to my case, I have the value in miles returned by the odometer (total HTTP requests). I have no clue what a clock poller or what the rest of that example means.
Here is a snippet of my poll below:
<CustomPoller UniqueName="sysStatHttpRequests" Description="The total number of HTTP requests." OID="188.8.131.52.4.1.33184.108.40.206.2.1.56" MIB="F5-BIGIP-SYSTEM-MIB:sysStatHttpRequests" SNMPGetType="GetNext" NetObjectPrefix="N" GroupName="F5" PollerType="C" Parser="Counter" IncludeHistory="True" Unit="" TimeUnitId="0" TimeUnitQuantity="0" DefaultDisplayTimeUnitId="0" Formula="" LabelType="" LabelDetail="">