[rrd-users] Re: Data not entering RRD, only "nan" values

BigglesZX biggleszx at gmail.com
Fri Jun 16 11:08:05 MEST 2006

On 6/16/06, Alex van den Bogaerdt <alex at ergens.op.het.net> wrote:
> On Thu, Jun 15, 2006 at 11:09:17PM +0100, BigglesZX wrote:
> > Hi all,
> >
> > I'm trying to graph packet and byte counts from iptables, but all I
> > get is "nan" in the RRD.
> >
> > I used this command to create the RRD:
> >
> > > rrdtool create chatter.rrd --start N DS:packets:GAUGE:60:0:U DS:bytes:GAUGE:60:0:U RRA:AVERAGE:0.5:1:720
> Where did you get "--start N" from ?

I've seen --start N in several examples. I understood it to mean "now".

> Why those "...GE:60:..." ?
> > > rrdtool update chatter.rrd N:$packets:$bytes
> Using "N:" every 60 seconds _approximately_ together with a
> heartbeat of 60 ???  Where did you get this idea?

Having reread the rrd-beginners tutorial with a fresh brain, I see
that this is indeed wrong. I've changed the heartbeat of the DSs to
120 and included "--step 60" in the create command, hopefully this
will get me somewhere.

In my reading of rrd-beginners I failed to notice that the example DSs
had a heartbeat of 600 yet the tutorial said they were supposed to
update every *300*. I failed to notice this :-).

> For all of the above comments:  I am _not_ saying it is wrong per se.
> But you should be able to defend your choices.  If you cannot, it is
> because you did not understand what you are asking rrdtool to do. And
> thus rrdtool may be doing something different than you expect. This
> in turn may very well be why you do not get the results you expect.
> > Whenever I try to generate a graph, with the following for example:
> >
> > > rrdtool graph chatter.png -t "ResNet Chatter Data" DEF:Packets=chatter.rrd:packets:AVERAGE
> >
> > I get the "0x0" "I'm not playing" message, and no graph. When I use
> You are _not_ creating a graph.  That is not because something goes wrong,
> unless you consider the problem between keyboard and chair.  Compare your
> command against any(!) of the examples creating images.

Revised my command thus:

> rrdtool graph chatter.png -t "ResNet Chatter Data" --start 1150361844 --end 1150361844 DEF:Packets=chatter.rrd:packets:AVERAGE DEF:Bytes=chatter.rrd:bytes:AVERAGE LINE:Packets#222222 LINE:Bytes#444444

A graph is now created and I'm getting some data :-D.

> > I've been poking away at this for hours and I can't figure out what's
> > wrong - why the data isn't going in. If anyone could shed any light on
> > this it would be much appreciated!
> Try the tutorials, the information on my site and the documentation.
> --
> Alex van den Bogaerdt
> http://www.vandenbogaerdt.nl/rrdtool/

Thanks for your help, guess it pays to reread the tutorials after a
good night's sleep :-).

Best regards,


biggleszx at biggleszx.com
ICQ 104870111

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