[rrd-users] Re: Graphing total bandwidth usage

alex at ergens.op.Het.Net alex at ergens.op.Het.Net
Thu Mar 2 17:04:07 MET 2000

Simon Amor wrote:
>  I've just started using RRDtool-1.0.13 to log byte counts for each port on
> each switch so we can monitor bandwidth for each server. The values are
> combined in/out bytes instead of separate, but this isn't too much of a
> problem. When I try and graph the information, I end up with what looks like
> deltas rather than absolute values.

That is correct.  They look like delta's but in fact they represent the
delta of the data divided by delta of the time.  This way, you should
end up with octets per second.
If you want to log your actual counter values, you should use the GAUGE
data type, not the COUNTER.  Even in that case, you may end up with
values that are not exactly what you put in the RRD (due to interpolation)

> The rrd was created using:
> RRDs::create("s1g1.rrd",
>      "DS:p1:COUNTER:600:0:4294967295",
>      "DS:p2:COUNTER:600:0:4294967295",
>      "DS:p3:COUNTER:600:0:4294967295",
> ...
>      "DS:p24:COUNTER:600:0:4294967295",
>      "RRA:MAX:0.5:1:600",
>      "RRA:MAX:0.5:6:700",
>      "RRA:MAX:0.5:24:775",
>       "RRA:MAX:0.5:288:797");

looking good

> Data gathered from snmpwalk via a perl script is added every 5 minutes using
> RRDs::update("s1g1.rrd", "N:$data");

looking good

> rrdtool fetch s1g1.rrd MAX shows a number of values, but they're all
> floating point instead of being a 32bit int. What am I doing wrong?

Nothing.  This is normal as they are actually stored as floats...

> To graph the data, I'm using:
> rrdtool graph s1g1p1.gif --start -86400 DEF:in=s1g1.rrd:p1:MAX
> AREA:in#00FF00:"Traffic"
> Which RRA is it actually using to display the graph?

It will use the RRA which can provide the data in the highest resolution
possible.  In this case, you are asking for a days worth of data and
this will be available in the first RRA (600 times 5 minutes is more
than two days).

 / 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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