In HBASE-19064 we aim to implement sync replication feature for HBase. You can see the design doc for more details on how it works
https://docs.google.com/document/d/193D3aOxD-muPIZuQfI4Zo3_qg6-Nepeu_kraYJVQkiE/edit# And now the feature basically works, we have tested it on real clusters, and also provide the operational documentation in the ref guide. You can see the 'Synchronous Replication' section in the ref guide of branch HBASE-19064. There are known limitations for this feature, and we have created HBASE-20422 to track them. Please vote: [+1] Agree [-1] Disagree [0] Neutral Thanks.
