Round Robin Databases are a system to store and display time-series data (i.e. network bandwidth, machine-room temperature, server load average). Every now and then, something significant happens that may result in a noticeable discontinuity on such graphs. Displaying such events on the graphs may be very useful to provide additional information to the viewer.

For this reason, drraw now supports a very simple interface for events. Since these cannot be stored in RRD files, extra files are needed. These files should contain one event per line, from the oldest to the most recent, in the following format: