Automating RDS Postgres to Aurora Postgres Migration

Netflix's Online Data Stores team automated the migration of nearly 400 RDS PostgreSQL clusters to Aurora PostgreSQL using a self-service workflow. The solution leverages Aurora read replicas for continuous replication, achieving ~10 minute downtime windows by coordinating traffic quiescence through their Data Access Layer proxy. Key technical challenges included enforcing zero data loss without database credentials, handling replication slot lag validation (the 0→64MB oscillation pattern), and managing CDC consumers through backfill. The workflow automates parameter group migration, security group manipulation for traffic control, and uses OldestReplicationSlotLag metrics to verify synchronization before promotion.