What methods have you used or know for ensuring high fault tolerance in PostgreSQL?

The following methods are used to ensure high availability in PostgreSQL:

• Replication: creating copies of the database on other servers (master-slave or streaming replication) so that in case of a failure of the primary server, a replica can be switched to.
• Automatic failover: using tools (e.g., Patroni, repmgr) to automatically switch to a replica in case of master failure.
• Backups: regular creation of backups (pg_dump, pg_basebackup) for data recovery in case of data loss.
• Monitoring and alerting: tracking server and replication status for quick response.
• Use of clusters and distributed systems: for example, Citus for scaling and high availability.

Example: setting up streaming replication allows having a hot standby that is synchronized with the primary server almost in real-time.