Curve Fitting Graphs

[dononeil]

Is there any way to create a 'running average' on a graph for an extended time period?

For example, see the mock up below, where the red line represents a curve fitted running averatge for the whole time window (hand drawn approximate).

Using the average consolidation function doesn't change the graph.. since it's still a '5 minute' average.... what I'm looking for is a 1 hour or more 'running' average.

[gandalf]

Please use a CDEF that defines the "TREND" function, see man rrdgraph_rpn
Reinhard

[dononeil]

Please use a CDEF that defines the "TREND" function, see man rrdgraph_rpn
Reinhard

There doesn't seem to be a way to access the "TREND" cdef in Cacti RRD config... only min/max/avg/last. Am I looking in the wrong place, or does Cacti not support this yet?

[Howie]

Please use a CDEF that defines the "TREND" function, see man rrdgraph_rpn
Reinhard

There doesn't seem to be a way to access the "TREND" cdef in Cacti RRD config... only min/max/avg/last. Am I looking in the wrong place, or does Cacti not support this yet?

You're looking in the wrong place - Click Graph Management, and a sub-menu called CDEFs appears. That's where you want to be.

However, as far as I can see, Cacti doesn't support CDEFs with TREND - that isn't in the list of available functions...

[dononeil]

Please use a CDEF that defines the "TREND" function, see man rrdgraph_rpn
Reinhard

There doesn't seem to be a way to access the "TREND" cdef in Cacti RRD config... only min/max/avg/last. Am I looking in the wrong place, or does Cacti not support this yet?

You're looking in the wrong place - Click Graph Management, and a sub-menu called CDEFs appears. That's where you want to be.

However, as far as I can see, Cacti doesn't support CDEFs with TREND - that isn't in the list of available functions...

Yeah, I looked there too and didn't see anything either. So, I guess I'm out of luck, or we need a new feature.

[mrnoodle]

You can create your hourly trend line with the following CDEF (give it whatever name you like) with a single custom string:


CURRENT_DATA_SOURCE,3600,TREND


Just add a second Line item to your graph and use the CDEF define above for the line as well as the legend.

You may have to convert bits to bytes first to ensure your data remains consistent.

[dononeil]

Thanks... that did the trick... although there is a 1 hour 'gap' in the graph at the beginning of each graph, most likely due to the fact that it is using the same data window that the grap is to generate the trend.

[gandalf]

although there is a 1 hour 'gap' in the graph at the beginning of each graph.

That's indeed the drawback of TREND
Reinhard

[hurdad]

I am having an issue occasionally when using this trending CDEF.
The current trend value will drop to zero see attachment.

[hurdad]

Anyone?