Failover of Primary database in Oracle Data Gaurd

If by some how Primary database is not available then we can activate or configure standby database as a Primary database. When we activate standby database as primary , then we can have data in our new primary upto the last redo transmitted and applied.

If possible your old primary is accessible then try to perform a switchover

PFB steps to activate standby database as new primary :-

SQL> ALTER DATABASE RECOVER MANAGED STANDBY DATABASE FINISH;

Database altered.

SQL> ALTER DATABASE ACTIVATE STANDBY DATABASE;

Database altered.

SQL> select open_mode from v$database;

OPEN_MODE
--------------------
MOUNTED

SQL> alter database open;

Database altered.

SQL> select open_mode from v$database;

OPEN_MODE
--------------------
READ WRITE

Our new primary database is ready to be use. Take a RMAN Backup of new primary database immediately to be on Safer side.

Switchover/switchback are safe for both primary and standby database, but failover makes the Original primary database useless for converting to a standby database . If flashback database is not enabled then Original Primary must be restored from a previous backup and then recreated as a standby database.

--NOTE :- Always have your Primary database and standby database configured with FLASHBACK, so that in event of failover , original primary can be flashed back to the time before failover and can be easily converted to standby.

Find out the scn at which this standby database become primary , this SCN can be used to flashback or recover your original primary as a standby database.

SQL> SELECT TO_CHAR(STANDBY_BECAME_PRIMARY_SCN) FROM V$DATABASE;

TO_CHAR(STANDBY_BECAME_PRIMARY_SCN)
----------------------------------------
1120211

PFB link to Convert a Failed Primary Into a Physical Standby Database Using Flashback Database.

PFB link to Convert a Failed Primary into a Physical Standby Database Using RMAN Backups.

I hope this article helped you.

Regards,
Amit Rath