Backing up an Oracle Data Guard environment

In our case, we simulate a site failure by shutting down (abort) the primary database oracle2

and deleting all database files:

SQL> shutdown abort

ORACLE instance shut down.

SQL>

On the standby, verify that there are no gaps in the archived redo log files by querying the

v$archive_gap view. In case there are some, try to copy the missing archive logs and register

them on the standby (this procedure is described in the Oracle Data Guard manual):

SQL> SELECT THREAD#, LOW_SEQUENCE#, HIGH_SEQUENCE# FROM V$ARCHIVE_GAP;

no rows selected

SQL>

Start the failover operation on the physical standby database. The command below assumes

you have standby redo log files. If not, include the clause “finish skip standby logfile” at the

end.

SQL> ALTER DATABASE RECOVER MANAGED STANDBY DATABASE FINISH;

Database altered.

SQL>

Once the recovery is finished in the standby, switch the standby (oracle1) to primary, and

startup the new primary database:

SQL> ALTER DATABASE COMMIT TO SWITCHOVER TO PRIMARY;

Database altered.

SQL> shutdown immediate;

ORA-01507: database not mounted

ORACLE instance shut down.

SQL> startup

ORACLE instance started.

Total System Global Area 536870912 bytes

Fixed Size 1310536 bytes

Variable Size 157548728 bytes

Database Buffers 377487360 bytes

Redo Buffers 524288 bytes

Database mounted.

Database opened.

SQL>

Now we have the former standby (SITE oracle1) running as primary. The former primary

database (SITE oracle2) is down because the db files were deleted.