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

[Richard Burton]

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.

"RRA:AVERAGE:0.5:1:129600","RRA:AVERAGE:0.5:10:38880","RRA:AVERAGE:0.5:3
0:52560","RRA:MAX:0.5:1:129600","RRA:MAX:0.5:10:38880","RRA:MAX:0.5:30:5
2560" 

and yes they are both using the same datasets.

Richard

> 
> >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.