HOW WE MIGRATED OUR POSTGRESQL DATABASE WITH 11 SECONDS DOWNTIME

Summary from the TLDR Web Dev newsletter

The migration of the GOV.UK Notify service's PostgreSQL database to an Amazon Web Services (AWS) account involved only 11 seconds of downtime. The migration was necessitated by the retirement of the GOV.UK’s original database platform. The upgrade was facilitated with the AWS Database Migration Service and a custom Python script.