DG Failover Steps

Purpose : Failover to standby database in case the primary database server crashes.
Assumptions : Primary Database SID : CHDP1
Standby Database SID : CHDS1
flashback is on


Now the Primary datbase server crashes and no longer accessible.

Step by Step Instructions.

Login to standby database (CHDS1)
SQL> alter database recover managed standby database finish force;
SQL> alter database commit to switchover to primary;

In very urgent situations when you can not wait for some of the logs to be applied.
SQL> alter database activate standby database;

Now at this point in time your standby database (CHDS1) becomes primary databse.

After few hours, your original primary database server (which has CHDP1 database) comes back up and you wanted to make it (CHDP1) a standby database.

Login to CHDS1

SQL> select to_char(standby_became_primary_scn) from v$database;
TO_CHAR(STANDBY_BECAME_PRIMARY_SCN)
--------------------------------------------------
1234567

Login to CHDP1
SQL> startup mount;
SQL> flashback database to scn 1234567;
SQL> alter database convert to physical standby;
SQL> shutdown immediate;
SQL> startup mount;