MRTG-RRD(1) mrtg MRTG-RRD(1)
mrtg-rrd - How to use RRDtool with MRTG
After using MRTG for some time you may find some limitations. Mostly in
the areas of performance and graphing flexibility. These are exactly
the areas addressed by rrdtool. To learn more about RRDtool check out
its website on
When using mrtg with RRDtool you are replacing rateup with the RRDtool
perl module RRDs.pm. To enable RRDtool support in mrtg you have to add
MRTG needs access to both the RRDtool perl module RRDs.pm and to the
If these two items are not installed in locations where perl can find
them on its own, then you can use the following two parameters to sup-
ply the appropriate directories.
For the location of the rrdtool executable you put
For the location of the perl module it would be:
When you have made this modification to the configuration file, several
things will happen when you run mrtg again with the new config file:
1. mrtg will take all your old ".log" files and convert them to ".rrd"
format. (The ".log" files don't get touched in the process, so if
things don't work out they are still there.)
2. mrtg will use rrdtool to update its databases. These will have a
new format called rrd which is totally different than the native
log format of the classic mrtg.
3. mrtg will not create any webpages of graphs anymore. It will only
query the routers for traffic information and update its rrd
The advantage of whole thing is that the mrtg will become much faster.
Expect the runtime to drop to 20% of the previous value. (I would like
to get some feedback on this from folks with large installations)
Mind you though, while the logging process of RRDtool is very fast, you
are also gaining some time by neither creating graphs nor updating web-
pages. The idea behind this is that it is more efficient to create
graphs and webpages on demmand. Using a cgi script.
At the moment there is no official script to do this, but two con-
tributers have created such scripts:
Was the first program to take over the webpage creation and graph-
ing task. It has been developed by Rainer Bawidamann <Rainer.Baw-
firstname.lastname@example.org>. You can find a copy on Rainers web-
The program comes with its own documentation
routers.cgi, servers.cgi and generic.cgi
are other cgi frontends to mrtg running with rrdtool. Thier main
difference to 14all is, that the web pages it creates are much more
stylish than the ones from mrtg. These tools have been written by
Steve Shipway <email@example.com>. You can find a copy in
The scripts comes with their own installation instructions.
Just as a side note: MRTG-3 will be based entirely on rrdtool technol-
ogy. But don't wait for it ... get going now!
Tobias Oetiker <firstname.lastname@example.org>
3rd Berkeley Distribution 2.9.17 MRTG-RRD(1)