Database Migration Strategy — Blue-Green Deployments. The recommended approach for production database migrations in v3 environments is the blue-green deployment pattern with shadow writes. In this pattern, the "blue" environment represents the current production database, while the "green" environment is a freshly provisioned replica where schema changes are applied and validated. During the migration window, the application layer performs dual writes to both environments, ensuring that the green database accumulates all new data alongside the schema changes. The shadow-write period should last a minimum of 24 hours to capture a full business cycle. Data consistency is validated by computing row-count checksums and sampling random records for field-level comparison. Once validation passes, traffic is switched from blue to green by updating the load-balancer configuration. The blue environment is retained for 72 hours as a rollback target; reverting is as simple as re-pointing the load balancer. This strategy eliminates downtime for schema migrations and provides a safe, well-tested rollback mechanism.