RRDtool is a high performance data logging and graphing system for time series data (i.e. network bandwidth, machine-room temperature, server load average, etc). RRDtool can be easily integrated in shell scripts, perl, python, ruby, lua or tcl applications. It stores the data in a very compact way that will not expand over time, and it presents useful graphs by processing the data to enforce a certain data density. This package includes the main software and perl bindings.
WWW: http://oss.oetiker.ch/rrdtool/