Copy DB from live [blue] to staging [green], then run migrations and test. Do this several times. This should give you confidence that the migrations behave as

Copy DB from live [blue] to staging [green], then run migrations and test. Do this several times. This should give you confidence that the migrations behave as intended before you flip from blue to green for production & run the migrations for real. If you have "big data" you can use schemaless migrations, for example never rename a column, instead add a new column, update the app to deal with both columns, then in a subsequent update remove the old column. You can also avoid migrations [use mongo instead of relational DB, for example]. I recommend Fowler's "DB Refactoring" book for further reading. http://martinfowler.com/books/refactoringDatabases.html http://martinfowler.com/books/refactoringDatabases.html