PostgreSQL High Availability: A Practical Guide for Production

Your application is live. Customers are using it. The database goes down. How long before traffic routes around the failure? Ten seconds? Five minutes? Never, because you're paged at 2 AM and have to manually promote a replica while the on-call engineer Slacks you asking if the database is "doing a thing"? PostgreSQL high availability is one of those topics that looks straightforward in blog posts and turns out to be deeply humbling when you actually implement it in production. This guide covers how PostgreSQL HA actually works, the main tools people use, what typically goes wrong, and when the complexity of DIY HA stops being worth it. What "High Availability" Means for PostgreSQL High availability means your database keeps serving requests even when individual components fail. For PostgreSQL, that typically requires three things working together: Data replication — at least one copy of your data exists on a server other than the primary Failure detection — something notices when the