RRD stands for Round Robin Database. RRD is an OpenSource time-series database (TSDB) written by Tobais Oetiker, used for storing numeric data over time, with the ability to reduce resolution of older data through various consolidation functions.

I wrote the Perl CPAN module RRD::Simple which provides a simple interface to RRD.

The RRD software homepage is http://oss.oetiker.ch/rrdtool.