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Tuesday, July 18, 2017

Failover to a Physical Standby Database When data protection mode is in MAXIMUM PROTECTION or MAXIMUM AVAILABILITY

Step 1:

Use the following procedure when the data protection mode is in MAXIMUM PROTECTION or MAXIMUM AVAILABILITY:

Before starting the failover operation, update the initialization parameter file on the physical Oracle instance
that is used for failover.  Include other standby databases in the Data Guard environment used as the archival destination
so that after the failover, the redo data can be archived from the new primary database to other standby databases.


Step 2:

In order to initiate the failover operation, the target physical Oracle instance should be placed
in MAXIMUM PERFORMANCE data protection mode using the following statement:

ALTER DATABASE SET Oracle instance TO MAXIMIZE PERFORMANCE.


Step 3 :

Allow the MRP to finish applying the redo data from the archived redo log file and the standby redo log files.

Step 4 :

Issuing the following statement will cause the MRP to terminate when it has applied all the available redo data:

ALTER DATABASE RECOVER MANAGED Oracle instance FINISH;

In Case If the standby redo log files on the target physical Oracle instance are corrupt,
or it is not desirable to apply the changes that are in the standby
redo log file, MRP can be completed by skipping the standby redo logs by using the following statement:

ALTER DATABASE RECOVER MANAGED Oracle instance FINISH SKIP STANDBY LOGFILE;

Step 5:

Once the MRP has finished applying all the redo data, issue the following statement to transition the physical
Oracle instance to the primary role. Status of managed recovery process
can be obtained from the v$managed_standby view or from the alert log file.

ALTER DATABASE COMMIT TO SWITCHOVER TO PRIMARY;

Step 6:

On all other standby databases, both physical and logical, register the standby
redo log file from the new primary database. The following statement will register
a log file with a database, and if the recovery process is running on a database,
the redo data from the log file will be applied:

ALTER DATABASE REGISTER LOGFILE ‘filespec’;

Step 7:

Finally, restart the new primary database to enable the read/write operation.
Update the Oracle Net configuration so that the new primary database will start serving the requests from applications.

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