Quite common case and in regular base we can follow most used scenarios such as : 1. Prepare few databases clone and perform dry-run, compatibility testing using demo/testing apps. 2. Prepare on-the-fly switching using common method such as load-balancing or database replication. 3. Testing and dry-run once the main-backup already setup before conduct main application server to be connected 4. Pre-initial launch for production server after completed testing using demo/test data to make sure it ran smoothly 5. Deploy and monitor switching process, prepare for rollback data if few errors occured, dont wait while process completed or it cant be reversed.

Minimizing Downtime in Critical Database Migrations In one migration, we moved a high-traffic e-commerce database with near-zero downtime. Key strategies: - Blue-Green Deployment: We set up a parallel environment, tested rigorously, and switched traffic seamlessly. - Chunked Data Transfer: Instead of a full migration at once, we replicated data incrementally using CDC (Change Data Capture). - Rollback Ready: We had a tested rollback plan to mitigate unexpected failures.

High level plan: 1. It depends on database technology - Sql server, PostgresSql, MySql, Oracle, etc. 2. It depends of database size and its architecture 3. It depends on server reources, plus network latency 4. Dry run test is required in order to prepare proper action plan, to clear from bugs if there are any, etc. 5. To check what is the backup solution 6. To preprare roll back plan

It just how effectively you are planning your migration strategy in discussion with business and application team. A collaborative approach needs to be taken with tests or dry runs in hand. Make sure to mitigate gaps if any came across during dry runs. Most importantly database migration must have a full proof roll back plan in place to avoid a critical situation.