Contents
How do I get high availability in PostgreSQL?
Objectives
- Set up two Compute Engine instances running Postgres.
- Create a new table for a guestbook app.
- Configure the primary server.
- Back up the primary server to the standby server.
- Configure the standby server to run in Hot Standby mode.
- Start the standby server and test it.
What is failover in Postgres?
Failover is the ability of a system to continue functioning even if some failure occurs. In the case of PostgreSQL, there are different tools that allow you to implement a database cluster that is resilient to failures. One redundancy mechanism available natively in PostgreSQL is replication.
What is streaming in PostgreSQL?
PostgreSQL streaming replication is based on transferring the WAL files from the primary to the target database. PostgreSQL streaming replication is implemented using a master-slave configuration. The master is known as the primary instance and handles the primary database and its operations.
What is PG Auto Failover for Postgres high availability?
pg_auto_failover is an extension to Postgres built for high availability (HA), that monitors and manages failover for Postgres clusters. Our guiding principles from day one have been simplicity, and correctness. Since pg_auto_failover is open source, you can find it on GitHub and it’s easy to try out.
What does the term failover mean in PostgreSQL?
Failover is the term to describe the recovery process, which in PostgreSQL, can take some time, particularly as PostgreSQL itself does not provide built-in tools for detecting server failures.
How does PAF help with PostgreSQL failover?
Once your PostgreSQL cluster built using internal streaming replication, PAF is able to expose to Pacemaker what is the current status of the PostgreSQL instance on each node: primary, standby, stopped, catching up, etc. Should a failure occurs on the primary, Pacemaker will try to recover it by default.
How to signal that PostgreSQL is in recovery mode?
In previous versions of Postgres, the recovery.conf file was used to signal to PostgreSQL that we expect the server to remain in recovery mode, either as a PITR instance or as a standby instance. However, in Postgres 12 you signal that by using either the standby.signal or the recovery.signal file.