Load balancing

Since Cassandra is a distributed database with the ability to add and remove nodes easily, it's important for the client to be able to send requests to new nodes that join the cluster, or to stop sending requests to removed or dead nodes.

Some databases use special middle-man processes to broker requests to available nodes, thus relieving the client of the requirement to maintain a list of hosts. Since Cassandra is a peer-to-peer system, with no special nodes or broker processes, the client must be aware of the topology of the cluster.

Tip

You should not use a load balancer between the client and Cassandra, as the client handles this via its load balancing policies. Adding a separate load balancer will actually prevent the client from understanding the cluster, which is what allows it to perform many of its duties.

Behind the scenes, the native driver connects to the cluster and learns about the topology of the ring. While legacy Thrift-based clients were able to make use of an...