[rrd-users] Averaging Question
Chris Nighswonger
cnighswonger at foundations.edu
Thu Mar 10 17:51:39 CET 2011
Sorry to answer my own post, but it may help some other searching soul.
On Thu, Mar 10, 2011 at 8:44 AM, Chris Nighswonger <
cnighswonger at foundations.edu> wrote:
> I'm wondering if this is possible with rrdtool:
>
> I have a sensor which is logged once every 30 seconds.
>
> I would like to produce a graph on which each point represents a 15 min
> average of the sampled data.
>
> Here is the caveat: The graph should have as many points as there are 30
> second data points with each point representing the average of the previous
> 15 minutes worth of data points. So a sort of "running average" if you will.
>
>
This is called a Moving Average in statistics. (
http://en.wikipedia.org/wiki/Moving_average)
> I'm guessing some DEF or CDEF magic will be needed to do this.... but I'm
> no statistics guru. :-)
>
The magic is already there with the RPN notation 'TREND' and 'TRENDNAN.' (
http://oss.oetiker.ch/rrdtool/doc/rrdgraph_rpn.en.html#Set%20Operations)
Kudos to the devs for this super tool!
Kind Regards,
Chris
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