The Round Robin Database Tool (RRDtool) is a system to store and display time-series data (e.g. network bandwidth, machine-room temperature, server load average). It stores the data in Round Robin Databases (RRDs), a very compact way that will not expand over time. RRDtool processes the extracted data to enforce a certain data density, allowing for useful graphical representation of data values. . This package contains development files for the Lua 5.1 interface to RRDs.