CHAPTER 8Switchover and Failover
If you have been reading all the preceding chapters, you should now be fully versed in the Data Guard architecture; standby database creation, management, and monitoring; what the different standby database types offer (and what they do not); and what interfaces you can use to manage Data Guard. But up to now, you have learned only how to set up your database to be protected in the event of some sort of production failure. You haven’t yet learned how to use your standby database for the purpose for which it was created: to take over as the production database. This is where role transition comes into play.
Introduction to Role Transition
Role transition is divided into two basic functions: switchover and failover ...