AWS Database Migration Service (DMS) enables you to migrate databases to AWS quickly and securely while keeping the source database fully operational during the process. It supports both homogeneous migrations (e.g., Oracle to Oracle) and heterogeneous migrations (e.g., SQL Server to Amazon Aurora). DMS uses Change Data Capture (CDC) for continuous replication, ensuring the target stays synchronized with the source until cutover. Migration tasks run on a provisioned EC2 instance that acts as the replication server, providing a resilient and self-healing migration process with minimal downtime.