Monitoring is the key to provide reliable service. For distributed software, monitoring becomes more important and more complex. Fortunately, Cassandra has an excellent tool built in for monitoring. It is called nodetool. Apart from this, there are third-party tools to monitor Cassandra.

The purpose of monitoring is to be able to catch a problem before or as soon as it happens and resolve it. Therefore, this chapter will be a mix of monitoring, management (it comes with monitoring tools), and very quick troubleshooting tips. It familiarizes you with the Java Management Extension (JMX) interface that Cassandra provides and then moves on to accessing it via JConsole. Cassandra's nodetool—the application to monitor and administer Cassandra—is discussed in detail. Further, DataStax OpsCenter (the community version), which is an excellent web-based tool that stores performance history, is discussed. Nagios is another tool that can be used to monitor not only Cassandra but...