RRDtool is the OpenSource industry standard, high performance data logging and graphing system for time series data. Use it to write your custom monitoring shell scripts or create whole applications using its Perl, Python, Ruby, TCL or PHP bindings.

You can find details at http://oss.oetiker.ch/rrdtool/ .

Many products use RRDTool such as Cacti .

Drraw is a simple web based presentation front-end for RRDtool that allows you to interactively build graphs of your own design.