[rrd-users] couple of questions
linux at thehobsons.co.uk
Wed Sep 8 22:42:31 CEST 2010
Ricardo Kleemann wrote:
>I'm not yet very familiar with rrdtool, but could I read out data
>values for an arbitrary period between time1 and time2 and add up
>the values to come up with accumulated?
>I was thinking of a page where I could choose the dates and then
>have a graph drawn for those dates, including the accumulated values
That's another approach - export/dump the data from rrdtool and
process it externally. You can't do that in rrdtool graph - AFAIK,
you have to create a CDEF which is "value times span" and which
covers <span> period of time, and then use a VDEF to show the average
Form the docs :
>Note that currently only aggregation functions work in VDEF rpn
>expressions. Patches to change this are welcome.
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