High availability

PostgreSQL relies on replication for high availability, failover, and balancing read loads across multiple nodes. Replication ensures that data written to the primary PostgreSQL database is mirrored on one or more nodes. By virtue of having multiple nodes with an exact copy of the primary database available, the primary database can be replaced with a replica node in the event of a failure or outage on the primary server. Replica nodes can also be used as read only databases (sometimes called “read replicas”), allowing reads to be horizontally scaled by spreading the read query volume across multiple nodes.