I am using MRTG + RRDtool to monitor the bandwidth on each switchport of a Cisco Catalyst 2950 via snmp. Is MRTG capable of generating an hourly graph? With RRDtool I was able to set the interval to 1 minute in hopes of getting a more detailed graph, but the shortest timeframe the graph is 'Daily' graph (5 Minute Average) and the image is too small.
What I am looking to get out of this: I am looking to be able to visually monitor all of the switch ports and tell when port begins to have unusually high traffic, in real time (1 minute interval of snmp poll, graphs generated, and page refreshed).
Best Answer
You can use the rrdgraph command line tool to generate graphs using the rrd files that MRTG generates. You can inspect he rrd file and see how soon it is consolidating the data, if it does this only after a day then you will loose the resolution that you are after. So basically I would for where MRTG stores the rra templates and the rrd graph templates.
It might take you a little time but since RRD is the backend graphing library/toolset for MRTG, Cacti, Munin, etc it is worth learning. I blogged about some things you might want to do when creating your own graphs on the Server Fault blog here.
Hopefully someone more familiar with MRTG can give you more details on your specific issue with MRTG.