performance monitoring solutions #

MRTG http://oss.oetiker.ch/mrtg/
You have a router, you want to know what it does all day long? Then MRTG is for you. It will monitor SNMP network devices and draw pretty pictures showing how much traffic has passed through each interface.

Cacti http://cacti.net/
Cacti is a complete network graphing solution designed to harness the power of RRDTool's data storage and graphing functionality.

Munin http://munin.projects.linpro.no/
Using Munin you can easily monitor the performance of your computers, networks, SANs, applications, weather measurements and whatever comes to mind. It makes it easy to determine "what's different today" when a performance problem crops up. It makes it easy to see how you're doing capacity-wise on any resources.

Hyperic http://www.hyperic.com/
Open source systems monitoring, server monitoring, and IT management software. Developed for web apps and service provider scalability.