Neo4j 3.1 introduced support for a new type of clustering known as causal clustering. With causal clustering, a few core servers will be configured, along with many read replicas. The configuration for causal clustering is similar to HA clustering:
causal_clustering.initial_discovery_members=192.168.0.100:5000,192.168.0.101:5000,192.168.0.102:5000causal_clustering.expected_core_cluster_size=3dbms.mode=CORE
This will define the 192.168.0.100-102 instances as core servers. Note that dbms.mode is set to CORE. The ha.initial_hosts property is replaced with the causal_clustering.initial_discovery_members property. The expected number of core servers is defined with the causal_clustering.expected_core_cluster_size property.
