[rrd-users] How do I make a graph using more than one RRA?

[Opex system administrator]

Dear list.

I've been sitting here for two days reading manuals and tutorials 
regarding rrdtool. I think I've got pretty much things covered that I 
need to know. There is one thing that I'm not sure how works, that is 
how can I select which RRA to use when forming a graph?

For instance:
rrdtool create traffictest2.rrd --step 10 DS:traffic:GAUGE:20:0:U 
RRA:AVERAGE:0.5:30:360 RRA:AVERAGE:0.5:1:10

There are two RRAs each with different average values (even though there 
is nothing to average for the later one). Now I wan't to create a graph 
showing both RRAs. When creating the graph I define which DS to use but 
I can't find anywhere in the documentation or here on the list (haven't 
checked all the list out but big portion of it) how to select which RRA 
to use for each AREA/LINE/etc.

Here is how I create the graph:
rrdtool graph ~kos/www/rrd/traffictest2.png --start 1176148699 
DEF:trafficdef=traffictest2.rrd:traffic:AVERAGE AREA:trafficdef#FF0000

I only get one colored red AREA (as defined). But what do I do if I 
would like to use the other RRA and form an AREA with it?

I made a perl script to fill the database traffictest2.rrd with random 
values between 0 and 10000. I made a graph one minute ago and you can 
see it at http://virtual1.opex.is/~kos/rrd/traffictest2.png

I would like to thank you all for a great tool and good documentation.
PS. I haven't used Cacti or anything like that so this is really my 
first introduction to rrdtool. :-).

Thanks in advance.

-- 
Regards/Kveðja,
Kristinn Örn Sigurðsson - Iceland.