[rrd-users] Confusion about VDEF total and graph values

Alex van den Bogaerdt alex at vandenbogaerdt.nl
Thu Oct 13 15:41:23 CEST 2016

> Here's the code I use to create a graph from this rrd:
> The $ variables are defined somewhere else and represent actual color
> codes
> and the rrd file name.

Maybe it's just me, but I don't see anything there.

> Here's an example of generated graph:
> <http://rrd-mailinglists.937164.n2.nabble.com/file/n7583425/gaslast.png>

> I was expecting the total value mentioned below the graph to be equal to
> the
> sum of all values in the graph. But as you can see it is not (or I

There are no values in the graph. There are rates in the graph.

I focus on the big bars only. I see three of them, somewhere around 182u,
141u and 58u.
These are rates:  {something} per second.
Each bar is valid for an hour.

So, 3600 x 182u + 3600 x 141u + 3600 x 58u
= 3600 x (182u+141u+58u)
= 3600 x 381u
= 1371600u = 1371.600m

The rest is due to the rates I ignored, and perhaps some rounding

The main thing to remember: you are watching rates, not values.
You are adding surface, not height.


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