High Availability Guide : Administering and configuring HotStandby : Administering HotStandby with ADMIN COMMANDs (HotStandby API) : Performing HotStandby recovery and maintenance
  
Performing HotStandby recovery and maintenance
After a system failure or during server maintenance, you might have to perform HotStandby tasks such as, switching server states, shutting off HotStandby operations, synchronizing Primary and Secondary servers, and connecting HotStandby servers.
Procedure
1 Perform some or all of the following operations:
a Switch the server state.
This includes setting the Primary server to PRIMARY ALONE state, which continues accumulating transactions in the transaction log so that they can be sent to the Secondary later, or shutting down HotStandby.
b Synchronize the servers to be sure the Primary and Secondary databases are identical.
c Connect the Primary server to the Secondary server if the communication link is broken for some reason.
2 The same steps can be taken with HAC and HA Manager as follows:
a Press the Switch button in HA Manager. If the server needs to be shut down, press the Shutdown button in HA Manager.
b Set HAC instances to the ADMINISTRATIVE mode by pressing the Administrative buttons in HA Manager.
c Set HAC instances to AUTOMATIC mode by pressing the Automatic buttons in HA Manager.
What to do next
For details on reconnecting applications to Secondary or Primary databases, see Reconnecting to primary servers from applications.
Important: If HAC is used, either use HA Manager to perform administrative steps, or set HAC instances to ADMINISTRATIVE mode before you start the administration task.
See also
Administering HotStandby with ADMIN COMMANDs (HotStandby API)