[mrtg] Re: wrong logs?

Alex van den Bogaerdt alex at slot.hollandcasino.nl
Tue Nov 16 11:36:26 MET 1999

> well.  Question, can anyone explain in layman's terms what guage and 
> absolute are actually for.  The config docs were of absolutely no 
> help there.  It even confused me more.  I don't think that's the 

MRTG works with differences.  If a counter increases, the difference
is calculated between (now - five minutes) and (now).
The exact time interval is also calculated (approx. five minutes).

You now have an increase in 300 seconds and can therefore MRTG is able
to calculate the increase per second (bytes/sec).

Some things we monitor are not increasing counters.  Example is the
number of users on a terminal server.  It is wrong to calculate the
difference over five minutes.  This is an example of GAUGE.

The remaining option is ABSOLUTE.  This is almost the same as GAUGE.
For a normal counter, it is MRTG that calculates the difference in both
bytes and time.  When option absolute is used, the device calculates
the difference in bytes and MRTG calculates the difference in TIME.

GAUGE:     just remember the received value
ABSOLUTE:  divide the received value by the lime lapsed
COUNTER:   divide the increase by the time lapsed

Time   device     gauge  absolute  counter
        gives    result    result   result
T+00:05   300       300         1        1
T+00:10   600       600         2        1
T+00:15   900       900         3        1
T+00:20  1200      1200         4        1

If this helps, please spend some time improving the manual.

 / alex at slot.hollandcasino.nl                  alex at ergens.op.het.net \
| work                                                         private |
| My employer is capable of speaking therefore I speak only for myself |

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