In previous chapters, we have touched on the idea that Cassandra can automatically replicate across multiple data centers. There are other systems that allow for similar replication; however, the ease of configuration and general robustness set Cassandra apart. Let's take a detailed look at how this works.
You will recall from Chapter 3, Replication that replication is configured via CQL at the keyspace level. Since we're on the topic of multiple data centers, it's important to understand that you'll always want to use the NetworkTopologyStrategy, since the SimpleStrategy does not allow for setting replication factor for each data center.
Attempting to use SimpleStrategy in a multi-data center environment would result in random replica placement across data centers. Coordination traffic across nodes would incur significant latency, as requests would often require nodes in more than one data center to satisfy the requested consistency...
