[rrd-users] Newby questions

Pablo Chacin pchacin at sensefields.com
Tue Oct 30 10:01:06 CET 2012

Thanks Simon, that's a very compelling explanation on how to
handle this situation. Probably it worth putting in the RRDTools'
wiki to prevent others coming regularly and asking the same


P.S. Just one final question are these RPNs available when fetching
and exporting data? I don't want to actually graph data, but to
export it to other applications. Documentation is not clear.

On 10/30/2012 08:51 AM, Simon Hobson wrote:
> You can compute totals in RRD - the problem is that the way it does
> it isn't the way you want to do it *in this application*. Which ever
> way it's done, there will be a lot of people for whom that is not the
> right way. Even in one setup the requirements may change
> So there you are - which way should RRD do it ? Either way is both
> right and wrong. As it is, it's possible to work around it either way
> if you use the right calculations when extracting the data.
> If you want to assume zero, then this RPN will do the conversion for
> you, then work with the result :
> aa=a,UNKN,0,a,IF
> which means: if a is unknown then substitute 0, else use a.

Pablo Chacin
R&D Engineer
SenseFields SL
Tlf (+34) 93 418 05 85
Baixada de Gomis 1,
08023 Barcelona (Spain)

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