Step by Step Switchover and Switchback from Physical standby to Primary in Oracle 11g R2

 STEPS OF ACTIVE DATAGUARD SWITCHOVER

* Here Prim is a Primary and Stan is Standby Database*
                                 
Convert primary database to standby


First verify that the primary database can be switched to the standby role

 SQL>  select open_mode,database_role,switchover_status from v$database;

OPEN_MODE            DATABASE_ROLE    SWITCHOVER_STATUS
-------------------- ---------------- --------------------
READ WRITE           PRIMARY          TO STANDBY


CONNECT SYS/SYS123@PRIM AS SYSDBA
ALTER DATABASE COMMIT TO SWITCHOVER TO STANDBY WITH SESSION SHUTDOWN;

NOW DATABASE IS DOWN MODE

STARTUP
OR
{
STARTUP NOMOUNT;
ALTER DATABASE MOUNT STANDBY DATABASE;
ALTER DATABASE OPEN;
}

SQL> select switchover_status from v$database;

SWITCHOVER_STATUS
--------------------
RECOVERY NEEDED

-- Convert standby database to primary

CONNECT SYS/SYS123@STAN AS SYSDBA
ALTER DATABASE COMMIT TO SWITCHOVER TO PRIMARY WITH SESSION SHUTDOWN;

SQL> select status from v$instance;
STATUS
------------
MOUNTED

NOW DATABASE IS MOUNT MODE

ALTER DATABASE OPEN;

SQL> select status from v$instance;
STATUS
------------
OPEN


ON OLD PRIMARY

CONNECT SYS/SYS123@PRIM AS SYSDBA
ALTER DATABASE  RECOVER MANAGED STANDBY DATABASE USING CURRENT LOGFILE DISCONNECT FROM SESSION ;


SQL> select switchover_status from v$database;

SWITCHOVER_STATUS
--------------------
NOT ALLOWED




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For Switchback  follow in reverse order