[rrd-users] Wrong Data with rrdfetch

[Sam Umbach]

On 4/25/07, Alex van den Bogaerdt <alex at ergens.op.het.net> wrote:
> On Wed, Apr 25, 2007 at 07:08:02PM +0200, Christoph Schwabl wrote:
> > Hello,
> >
> > I get wrong (rounded) data with the rrdfetch command.
>
> No, you do not.  At least not in your example (I'm sure some
> rounding will occur, eventually, somewhere).
>
> > Is this normal? What should I do to correct this problem?
>
> You should RTFM http://oss.oetiker.ch/rrdtool/doc/rrdcreate.en.html
> section on counter types.
>
> Also see my site for some more information.
>
> Delta_value is 54000000000 (because you say so!), delta_time is 900
> (because of timestamps 1177498800 and 1177497900), thus the computed
> rate is 54000000000/900 = 60000000 = 6.0e+07

ABSOLUTE, COUNTER, and DERIVE data source types calculate a rate based
on the time since the last update.  If your input is already a rate,
you should use the GAUGE data source type.  GAUGE is used for things
like temperature, cache size/usage, CPU utilization, disk usage, etc.

Please see the details for the data source types in the rrdcreate documentation:
http://oss.oetiker.ch/rrdtool/doc/rrdcreate.en.html

-Sam