PostgreSQL High Availability

PostgreSQL cluster software provides robust solutions for high availability (HA) for critical business applications with log shipping and streaming replication methods, ensuring data redundancy and availability in local as well as in remote locations. In the AWS EC2/Azure VM environment, you must configure all redundancy for high availability by setting up one or many replicated standby instances, whereas in AWS RDS/Azure SQL Database, single or multiple availability zones for redundancy and fault tolerance are built into the product. Both EC2/Azure VM and RDS/Azure SQL Database replication environments follow the underlying pg_basebackup or snapshot procedures for setup of PostgreSQL replication. You have to check the status of the primary periodically with scripting methods in AWS EC2/Azure environments and the standby will be promoted to primary in the event of an outage to the primary site, whereas promotion to primary of a standby site is performed automatically by the managed database service. There are several third-party tools and extensions that help in promoting the standby to the primary role in the event of an outage to the primary site.