8. 8@Twitter
Replication State
Persistently stored in Zookeeper
Status
Master kill switch
Peers
List of remote target clusters
Queues
List of remaining HLogs to replicate and current
position in each log
11. 11@Twitter
End-point for shipping WAL entries
One instance for each queue
Runs as a separate thread on region server
Uses AdminProtocol RPC to synchronously
ship entries
Filters edits based on replication scope
Replication Source
12. 12@Twitter
Replication Sink
End-point for receiving shipped WAL entries
One instance per region server
Synchronously receives entries and applies
them using HTable
Batches rows in the same table
21. 21@Twitter
Peers znode
A set of remote clusters registered as possible
replication targets
Identified by peer id
Contains status of each peer cluster