In addition to distributing information across the cluster for even data distribution and cluster performance, you can also establish replica vBuckets within a single Couchbase cluster.
A copy of data from one bucket, known as a source will be copied to a destination, which we also refer to as the replica, or replica vBucket. The node that contains the replica vBucket is also referred to as the replica node while the node containing original data to be replicated is called a source node. Distribution of replica data is handled in the same way as data at a source node; portions of replica data will be distributed around the cluster to prevent a single point of failure.
After Couchbase has stored replica data at a destination node, the data will also be placed in a queue to be persisted on disk at that destination node. For more technical details about data replication within Couchbase clusters, or to learn about any configurations for replication, see Section 5.3, “Handling Replication within a Cluster”.
As of Couchbase Server 2.0, you are also able to perform replication between two Couchbase clusters. This is known as cross datacenter replication (XDCR) and can provide a copy of your data at a cluster which is closer to your users, or to provide the data in case of disaster recovery. For more information about replication between clusters via XDCR see Section 5.9, “Cross Datacenter Replication (XDCR)”.