I'm looking for recommendations for an MRTG -like graph application that is easy to install on an Redhat Enterprise 5 linux system running cpanel/whm that runs well alongside cpanel/whm and doesn't consume too many resources itself to provide web-accessible graphs of traffic, load, disk io, etc.

Years ago I really enjoyed hotsanic, but find it's no longer supported and could not get it to install well even on RHE3 (worked great back in the redhat 7-9 days.)

Anyone have some good current recommendations for redhat enterprise 5?

I like cacti myself http://cacti.net/

cacti looks quite interesting, but is also a bit overwhelming.

I have cacti itself setup, and have it graphing localhost load, logged in users, and disk space usage.

But now I'm overwhelmed and not sure how to go about graphing traffic on eth0.

Can you give me a quick start guide on setting cacti to graph eth0 traffic?

(I installed net-smtp from source on RHEL5, but I believe I need to do more configuration to get cacti and net-smtp to work together as I don't seem to get any graph data when trying traffic; or maybe I'm just not swift enough yet to setup cacti correctly...)

I may have been trying to be too "slick" with snmp-net version 3 instead of the simpler version 1. I think I'll try version 1 first and see if I can get that working...

Well it appears it is connecting with snmp-net version 1 as it shows details (like location, contact, etc.) there when it connects.

However, when I try to create a new graph for the device to graph traffic, I only get
Data Query [SNMP - Interface Statistics] Reload Associated Query
This data query returned 0 rows, perhaps there was a problem executing this data query. You can run this data query in debug mode to get more information.

+ Running data query [1].
+ Found type = '3' [snmp query].
+ Found data query XML file at '/usr/local/apache/htdocs/stats/resource/snmp_queries/interface.xml'
+ XML file parsed ok.
+ Executing SNMP walk for list of indexes @ '.1.3.6.1.2.1.2.2.1.1'
+ No SNMP data returned
+ Found data query XML file at '/usr/local/apache/htdocs/stats/resource/snmp_queries/interface.xml'
+ Found data query XML file at '/usr/local/apache/htdocs/stats/resource/snmp_queries/interface.xml'
+ Found data query XML file at '/usr/local/apache/htdocs/stats/resource/snmp_queries/interface.xml'

So I'm obviously doing something wrong still...

Got it graphing traffic now - my snmpd.conf file was wrong.

Care to share a how-to ?

I installed net-snmp from source.
Then I found this tutorial easer to follow than the main instructions: http://docs.cacti.net/node/137
To troubleshoot I removed the entire snmpd.conf installed by default and created a new snmpd.conf containing only
rocommunity public
disk /
I think it's easier to build it up from nearly blank like this (the above will work on its own)
I found cacti a bit laborious and cryptic to get started with while I was tired, but once you get used to it, it generates some pretty nice graph stats I'm only using it in a very basic form right now though on localhost.

One other cacti gotcha -- once you get SNMP working, under the data query where eth0 and lo should appear, make sure you click the green refresh button (green circle icon on the left.) Mine kept showing "this data query returned 0 rows, perhaps there was a problem executing this data query. You can run this data query in debug mode to get more information." even though the snmp connection was showing ok at the top. And even though I clicked save and opened the page afresh several times. Wasted a half hour until I realized I needed to actually click the green refresh button and then lo and behold, there was eth 0 so I could select the graph type (in/out + traffic) from the dropdown and actually create the graph.

After spending a couple days playing with cacti, I see WHM includes preconfigured Munin as a cPanel plugin now.

Any thoughts on how Munin compares with Cacti in the long run?

The graphs from Munin out of the box with the WHM plugin are pretty impressive. I like the whm-configed munin overlay display of memory, iostat, cpu, etc. and find these graphs visually appealing and very easy to read and appreciate having all the information on one graph vs. many. And the out-of-the-box munin config is pretty extensive, including apache, exim, and mysql as well as the standard system status graphs.