[rrd-users] rrdtool fetch showing different values?

Simon Hobson linux at thehobsons.co.uk
Tue Aug 23 12:43:17 CEST 2011

norus wrote:

>I'm pretty much new to rrdtool, so I wanted to ask some beginner questions.
>Currently, I'm monitoring load average on some remote Linux host. A Fabric
>script is gathering stats remotely and writes to data.txt in the following
>Here's how I created my rrd file and how I update it:
>Now my question is: how come the values in data.txt don't correspond to
>those stored in rrd?
>*rrdtool fetch:*

Hmm, rather blank example there !

Your question is a very FAQ. RRD does **NOT** store the data you 
enter - it will **always** normalise and consolidate your data 
according to the rules you gave it when you created the RRD file. The 
only way to get out what you put in is for you to ensure your data is 
already normalised so that the normalisation done by RRD is a null 

Alex has a very good tutorial on "Rates, normalizing and 
consolidating" which "explains how RRDtool processes its input data, 
normalization and consolidation are described there as well as some 
generic stuff about the properties of an RRA".

Simon Hobson

Visit http://www.magpiesnestpublishing.co.uk/ for books by acclaimed
author Gladys Hobson. Novels - poetry - short stories - ideal as
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