[mrtg] mrtg-questions

Daniel J McDonald dan.mcdonald at austinenergy.com
Mon Dec 8 19:10:13 CET 2008

On Mon, 2008-12-08 at 09:51 -0800, nangineni praneeth wrote:

> Hello everyone
>                            I am working on a project titled network
> monitoring and would like to add few details in my documentation...I
> searched for these question over the web but couldnt find anything....
> 1)  Why are we specifying max bytes when we are using MRTG to monitor
> rtt, packetloss,cpuload etc?.I mean rtt or other variables like
> packetloss have nothing to do with max bytes....

It's called MaxBytes because mrtg was originally designed to monitor
traffic, and non-backward compatible changes are hugely frowned upon.

> I know that MRTG requires that options but couldnt figure out why??

For counters, it needs to know the max so it can detect counter
roll-overs.  For non-counters, it needs to know the max so it can
determine percentage correctly.

> Would be grateful if someone could answer how max bytes option is
> related to these variables

It's the maximum value expected to be present.

> 2)options [:]:integer.......what does this option....The mrtg website
> says "Print summary lines below graph as integers without
> commas"....was little confused by this...can anyone clearly tell me
> what this option does...

I think that removes the k/m/g suffixes, but I haven't played with
rateup in a while, so I don't recall.

> 3) I can monitor rtt and packet loss with MRTG by making use of
> mrtg-ping-probe....
>    I did the following from cmd
> c:/mrtg/bin/>perl mrtg -ping -probe and it returned me two
> values 
>  47
>  48 

More than likely, inbound latency and outbound latency, but you would
need to check the mrtg-ping-probe file to make certain.

> what does these two values represent......are these two values
> representing the incoming bytes counT and external bytes count...again
> why am i speaking in terms of bytes count when monitoring ping and
> rtt...
> I know these are lot of questions....But since i am working on this
> project i must be able to answer these questions.........tried lots on
> the web but couldnt find answers for these
> Would be really thankful if someone helps me out
> Regards
> Venkat.....

Dan McDonald, CCIE #2495, CISSP# 78281, CNX

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