RRDTool: A Round Robin Database for Network Monitoring

Abstract

RRDtool is a circular database which stores time series data. RRDtool assumes time-variable data in intervals of certain length. An interval is named as a step and specified upon creation of an RRD file which cannot be changed afterward. Because data may not always come at just the right time, RRDtool will automatically interpolate any submitted data. This is done to fit its internal timestamps. If we compare linear databases with RRD then we can say that RRD is non-linear like a circular queue. Usually, in a Round-Robin Database (RRD), time-series data like network bandwidth, memory usage, CPU load are stored. The data is stored in a non-linear way so that system storage footprint remains constant over time. This actually avoids resource-expensive purge jobs which reduce complexity. MySQL does NOT provide any such kind of storage engine. RRDtool has also the ability to create and feed this database. RRDtool stores data; that makes it a back end tool. The RRDtool command set allows the creation of graphs that makes it a front end tool as well. Other databases just stores data and cannot create graphs. RRD combined with NET-SNMP can collect data and using scripts we can generate beautiful real-time graphs which can be used for monitoring computer networks.