95th Percentile Datasource
I've been asked to re-implement some monitoring that we used to aggregate from MRTG data, and I'm immediately baffled because it looks like there's a built-in datasource to do what we need (at leas...
Forum Discussion
If you're looking at the SNMP_Network_Interfaces datasource, the 95th percentile datapoints in there are mistakes. They do not do what the developer thought. Those infix functions can only be used in virtual datapoints in graphs, not in a complex datapoint in a DataSource. The developers are aware of this and we should be getting a fixed version pushed out soon.
In the meantime, all you need to do is create a virtual datapoint on the custom graph and specify your percentile parameters there.
The thing to think about is that 95th percentile requires a sample of data. In the DataSource, there's only one piece of data: the current poll's result. So the 95th percentile of one datapoint is the datapoint itself. There appears to also be some funny math there as well since it seems to calculate 95% instead of the 95th percentile of that single datapoint. When you do it as a virtual graph, the graph's total included duration dictates what data can be included in the percentile calculation and you'll get a much more expected number.