Neo4j uses the Master-Slave replication model. All writes must go through the master and the slaves will be read only. Changes performed on the master will be pushed out to the slaves when the logical log is rotated (based on configured size or invoking a method on the master).
The online backup utility used to synchronize a destination Neo4j database from a source Neo4j database can be used to emulate “high availability” (HA) having the master replicating changes to read only slaves.
I didn’t know Neo4j supports a highly available setup. Since when?