A switchover is a planned role transition between the primary database and a standby database within the same Data Guard configuration. Switchover is used to reduce the downtime of production databases during any scheduled maintenance on the production server, to test the server capability or any changes at hardware level, or to check future role transitions. During switchover, there is no data loss and the role of each database changes from primary database to standby database and vice versa as shown in the following diagram:
Data Guard switchover is also a good way to move databases to new hardware. We can perform RMAN backup and restore the database to the new server, but the disadvantage of using RMAN is that we have to open the database with resetlogs. Another alternative would be shutting down the database and copying all files onto the new server. But this method will take a lot of time depending on the size of the database, and also it's not easy to perform this method...