PUBLIC MARKS with tags graphs & monitoring

Using Munin you can easily monitor the performance of your computers, networks, SANs, and quite possibly applications as well. 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 all limited resources.

Cacti is a complete network graphing solution designed to harness the power of RRDTool's data storage and graphing functionality. Cacti provides a fast poller, advanced graph templating, multiple data acquisition methods, and user management features out of the box.

MRTG is being used to graph all sorts of network devices as well as everything else from weather data to vending machines.

The industry standard data logging and graphing application. Use it to write your custom monitoring shell scripts or create whole applications using its Perl, Python or PHP bindings.

Cricket has two components, a collector and a grapher. The collector runs from cron every 5 minutes (or at a different rate, if you want), and stores data into a datastructure managed by RRD Tool. Later, when you want to check on the data you have collected, you can use a web-based interface to view graphs of the data.