[rrd-users] MAX values dependant on width of graph

Richard Burton richard at atomwide.com
Fri Mar 7 12:42:21 CET 2008

Hi Simon

Below are the variables I am using when creating the archive, so in
answer to your question I believe I am storing the RRA for MAX.


and yes they are both using the same datasets.


> >I wonder if someone could explain this to me, either I am missing
> >something or I have some errors in my scripts.
> >
> >It appears that when producing a graph the MAX values are 
> not calculated
> >on the actual absolute maximum value in the sampled data for 
> the given
> >time scale specified, but on the maximum value displayed on the graph
> >after the data has been aggregated to fit into the required 
> pixel width.
> >As such generating the same graph twice but with different width
> >settings produces 2 different MAX values?
> Are you certain that both graphs are using the same dataset ? When 
> changing the timespan of the graph, it's fairly easy to change which 
> RRA is used to produce the graph which could alter the values 
> returned.
> Also, I assume you are storing an RRA for MAX and not taking "MAX of 
> AVE" which is an easy mistake to make.

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