[mrtg] Peaks on graphs

Eric Brander mailinglists at rednarb.com
Fri Jul 11 20:02:17 CEST 2008

On Fri, Jul 11, 2008 at 11:12 AM, Gerardo Gálvez <g_galvezc at hotmail.com> wrote:
> Hello:
> I'm running the MRTG for monitor the traffic of some thousands of devices,
> but suddenly some graphs has record peaks of traffic which is not real (The
> typical device operates around 256 Kbps and the metioned peaks shows traffic
> of 6 Mbps)
> I wonder if this behaviour is associated with a maximum capacity of MRTG for
> manage thousands of devices, or maybe with a requirement regarding the
> memory and/or CPU of the used server.

Not sure why you had the peak. MRTG simply does math on the difference
between two readings. Not sure how quantity could impact that. Are you
running over the 5-minute polling window?

I don't monitor that many devices. However, to prevent impossible
peaks like this you may want to consider setting your MAXBYTES setting
to the actual maximum that can be expected on the interfaces. Doesn't
solve the actual problem but prevents it from skewing your graphs.


Eric Brander

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