By continuing our exploration of the building blocks that make up a WebSphere eXtreme Scale deployment, we delve further into shards, partitions, and replication in this chapter. Our focus this time is data availability. In Chapter 5, we learned how to create a scale-out deployment emphasizing total capacity. We'll now look at building redundancy into our deployment with replication. We'll look at reasons to add replication to a deployment and at the two different replica types.
Before we proceed, you should have a firm understanding of the relationship between shards and partitions. We use the
xsadmin tool and container log files to get a better idea of how shard placement and startup works. As we use