HBase supports cluster replication, which is a way to copy data between the HBase clusters. For example, it can be used as a way to easily ship edits from a real-time frontend cluster to a batch purpose cluster on the backend.
The basic architecture of an HBase replication is very practical. The master cluster captures write ahead log (WAL), and puts replicable Key/Values (edits of the column family with replication support) from the log into the replication queue. The replication message is then sent to the peer cluster, and then replayed on that cluster using its normal HBase client API. The master cluster also keeps the current position of the WAL being replicated in ZooKeeper for failure recovery.
Because the HBase replication is done asynchronously, the clusters participating in the replication can be geographically distant. It is not a problem if the connections between them are offline for some time, as the master cluster will track the replication, and recover...
