[mrtg] mrtg : option when mrtg cannot reach the targeted device

david.neau at orange.com david.neau at orange.com
Wed Nov 30 13:07:41 CET 2016

Hello Darren,

Thanks for your reply

In my case I use mrtg to read eth interface counters to plot traffic interface.

Based on your 2 options and if I m not mistaken :

1. Repeat the last known value :
if both values are the same, traffic plotted is zero, and if the next pooling is ok traffic displayed is higher than the reality ( twice if traffic is constant )

2. Log as zero :
Then when next pooling  is ok, traffic displayed is unrealistic ( huge spike )

Ideally when pooling failed , the traffic calculation should be done with the last valid pooling and the new one BUT over 10 mn ( if pooling is done each 5 mn )

Is there a way to this ?

Hoping to be clear ...


-----Message d'origine-----
De : Darren Murphy [mailto:darren at victoriajd.com] 
Envoyé : mercredi 30 novembre 2016 11:33
Cc : mrtg at lists.oetiker.ch
Objet : Re: [mrtg] mrtg : option when mrtg cannot reach the targeted device

On 29 November 2016 at 16:27,  <david.neau at orange.com> wrote:
> Hello,
> Does someone can explain what are the configuration options when mrtg 
> cannot reach the target ?

If MRTG cannot reach the target, then there will be no data for that polling cycle.
The default behaviour in this case is to repeat the last value.
If this is not desirable, then the 'unknaszero' option may be used, which will cause MRTG to log all unknown values as zero.

So essentially, there are two options:

1. Repeat the last known value
2. Log as zero

See http://oss.oetiker.ch/mrtg/doc/mrtg-reference.en.html



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