[mrtg] Weired behavior of MRTG
Alex van den Bogaerdt
alex at ergens.op.het.net
Mon Sep 10 16:15:44 CEST 2007
On Mon, Sep 10, 2007 at 06:37:37AM -0700, Peter wrote:
> > Peak hour... as in: a high consumer of bandwidth is present?
> > that's why I asked:
> > Why would such fluctuations be a problem? Are there devices
> > with gigabit ethernet (or similar) on the network?
> Yes, there are devices with gig interfaces on my network...
> > Many different consumers will create tiny fluctuations which are
> > hardly visible. Also, they tend to cancel each other out.
> tiny? it's not tiny!! look at the graphs again please! it's about 2.5 - 3gb !!! every day at the same time?
1: "tiny" are those fluctuations that you do _not_ see. In my sine wave
example, those are canceling each other out, leaving nothing more than
some hardly visible noise in an otherwise flat graph (not zero, but
relatively smooth at e.g. 3G).
2: The visible fluctuations are not tiny. But the could be the sum
of a couple smaller fluctuations which are themselves not quite
so visible. In my sine wave example, these are the ones amplifying
each other resulting in a higher amplitude.
3: Every day at the same time... if there is a problem in MRTG, I
expect a problem when counters wrap around which will NOT happen
at the same time every day.
4: If there's a problem in the configuration file, it will most
likely have to do with the total amount of throughput. In such
a case, there will be a significant difference between what MRTG
shows and what your spreadsheet shows. Double check your max and
absmax settings. And do allow for some slack (upto 10%)
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