Mike Gerdts wrote:
> 
> A key problem with rrdtool is that it doesn't store the actual values
> that you feed it - rather it weights the values given to the intervals
> you specify.  Suppose the most detailed portion of the rrd file is 1
> minute intervals and the following values are recorded:
> 
> MM:SS Value
> 00:15 100
> 01:15 50
> 
> The value stored in the rrd file at 01:00 will be something like 62.5
> (15/60 * 100 + 45/60 * 50).  I may be off on the exact algorithm, but
> just beware that data in doesn't look just like data out.  It is,
> however, quite sufficient for visualization and maybe some other
> analysis.

Hmm. I don't like that. I want to see the exact values as they were 
originally measured. I don't like seeing massaged data at all. If it 
needs massaging for some reason, let me do it and I can justify my 
methods to management.

> Do take a look at Brendan Gregg's blog and get to understand the
> graphs there.  Heat maps are a wonderful thing.  I'd love to see this
> as a standard graph option in rrdtool (and R, and ...).

Thanks, I will. :-)

Rainer
-- 
Mind the Gap
http://www.dragonhearth.com/blogs/rheilke

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