Developer's Guide
RRD is used by Zenoss to store and graph performance collection data. These data files have a fixed format that is decided at their creation time, and record data points at set intervals. This data is later consolidated into coarser time units (so as to reduce the total size of data files) and the RRD toolset also contains code to create graphs.
A few other interesting facts:
Zenoss is a gold-level sponsor of RRD.
The Renderserver sends RRD graphics to Web browsers.
