[rrd-users] Numbers

Simon Hobson linux at thehobsons.co.uk
Sun Jan 4 22:33:16 CET 2009

William R. Lorenz wrote:

>Shouldn't normalization only apply to non-GAUGE RRDs, or is this not 
>the case?  A gauge is a gauge regardless of the bin size, is that 
>not right?

No, normalisation is applied to ALL data types.

Consider that you have a rate of 0 from time 0 to time 150, and a 
rate of 2 from time 150 to time 600 - and a step size of 300. From 0 
to 300 you have half your bin at rate 0, and half at rate 2 - so the 
value stored for that bin is 1. From 300 to 600 the rate is uniform 
at 2, so 2 is stored.

Note that I said rate. ALL values are rates in rrd - they are either 
calculated (eg at time 0 your counter was 0, at time 150 your counter 
was 0, at time 300 your counter was 300, and your data type is 
counter), or you supply a value which is already a rate and your data 
type is gauge.

If you use data type gauge and supply updates of 0 at 0, 0 at 150, 2 
at (some future time >=600), then the same process happens - the 
average rate from 0 to 300 is still 1.

Simon Hobson

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