[mrtg] Re: Graph output when node is down?

[Stieers, Ken]

> Hi,
>   We had a remote site go down for about 2 hours yesterday 
> that was being
> monitored by mrtg.  The graphs for that node show 
> a steady in/output of about 300bytes on bri0/0?  Can anyone 
> tell me why this
> happens?  I would think the graph input for the port would at 
> least be 0. Or
> Does MRTG take the next reading it can get from the remote 
> site and fill in
> the unavailable time with this data producing the steady in/out rate?

Close...it takes the last reading and repeats it.  There is an option
(unknaszero) in 2.8.4 and higher that graphs unknown values as zeros. 

Here's the info from config.html. 

unknaszero 
Log unknown data as zero instead of the default behaviour of repeating the
last value seen. Be careful with this, often a flat line in the graph is
much more obvious than a line at 0. 

Ken

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