Fail back from Amazon RDS for Db2 to on-premises AIX Db2 using DMS

This article explains how to set up CDC-only reverse replication from Amazon RDS for Db2 back to on-premises AIX Db2 using AWS DMS over a private network for safe fail-back during migration validation.

• Configure reverse CDC replication from RDS for Db2 (source) to on-premises AIX Db2 (target) using AWS DMS
• Use private-only network architecture with AWS Direct Connect, VPC endpoints, and no public internet access
• Enable archive log retention, DATA CAPTURE CHANGES, and appropriate database user privileges on both source and target
• Deploy DMS replication instance in private subnet with security groups restricting traffic to private subnets only
• Monitor CDC latency metrics and validate data consistency before fail-back execution
• Execute fail-back by stopping CDC task, re-enabling constraints, and updating application connection strings
• Decommission reverse replication after 2-4 weeks of stable production operation to minimize costs

This temporary fail-back strategy provides a tested safety net during the post-cutover validation window, enabling quick rollback while preserving data integrity if issues arise after migrating Db2 workloads to AWS.