[collectd] Graphing rrd output of CPU plugin

[Bruno Prémont]

On Sun, 17 April 2011 lanas <lanas at securenet.net> wrote:
> On Sun, 17 Apr 2011 15:49:41 lanas <lanas at securenet.net> wrote :
> 
> >   Are there examples around for quickly graphing the out put of some
> > plugin modules (such as CPU) without having to use a web server (as
> > shown in first steps).  Simply producing a (some) graphic
> > file(s) from the files in cpu-0 directory for instance, to get a feel
> > about how it works and how collectd resulting data is worked with
> > rddtool. 
> 
> I've found that rrdtool info must be used first to get some names from
> a rrd file set up by collectd.

You don't have to if you know in advance how the RRD file(s) is/are
defined.

> ...
>
> I presume the name 'value' refers to the actual values received from
> the system where collectd run as a client (with the cpu module plugin).
> 
> A rrdtool fetch command would show the time stamps where values are
> found.  These time stamps can be used to narrow a graph.
> 
> So now a very simple graph can be made using:
> 
> /opt/rrdtool-1.4.5/bin/rrdtool graph cpuidlevalues.png \
>   --start 1303068900 --end 1303069810 \
>    DEF:cpuidlevalues=cpu-idle.rrd:value:AVERAGE \
>    LINE2:cpuidlevalues#FF0000
> 
> Maybe all collectd plugins are using the name 'value'.  Or maybe
> 'rddtool info' has to be run on every rrd file generated by collectd.  I
> certainly haven't looked at all documentation, but the cpu plugin
> documentation does not seem to mention that the ds-name keyword 'value'
> is used.

Look at collectd's types.db file for that names used for data series in
RRD files! That's the file based on which collectd instructs rrdtool to
generate the RRD files.

Bruno