As a system grows, an application matures, the cloud infrastructure starts to warn us about the failure of underlying hardware, or if you get hit by the TechCrunch effect, you may need to do one of these things: repair, backup, or scale up/down. Alternatively, the management might decide to have another data center setup just for the analysis of data (maybe using Hadoop) without affecting the user's experience for which the data is served from the existing data center. These tasks are an integral part of a system administrator's day job. Fortunately, all these tasks are fairly easy in Cassandra, and there is a lot of documentation available for it.

In this chapter, we will go through Cassandra's built-in DevOps tool and discuss how to scale a cluster up and shrink it down. We will also see how one can replace a dead node or just remove it, and let other nodes bear the extra load. Further, we...