Switchover and Failover steps

SWITCH OVER
1. SELECT SWITCHOVER_STATUS FROM V$DATABASE;
SWITCHOVER_STATUS
-----------------
TO STANDBY
1 row selected

2. ALTER DATABASE COMMIT TO SWITCHOVER TO PHYSICAL STANDBY;

3. SHUTDOWN IMMEDIATE;
STARTUP MOUNT;

4. SELECT SWITCHOVER_STATUS FROM V$DATABASE;

SWITCHOVER_STATUS
------------
TO_PRIAMRY


5. at standby ALTER DATABASE COMMIT TO SWITCHOVER TO PRIMARY;


6. alter database open [if db opened read only since last time it was started]
else shutdown and restart

7. ALTER SYSTEM SWITCH LOGFILE;



FAILOVER

First resolve gap:

A) Identify and resolve any gaps in the archived redo log files.
SQL> SELECT THREAD#, LOW_SEQUENCE#, HIGH_SEQUENCE# FROM V$ARCHIVE_GAP;
THREAD# LOW_SEQUENCE# HIGH_SEQUENCE#
---------- ------------- --------------
1 90 92


ALTER DATABASE REGISTER PHYSICAL LOGFILE 'filespec1';

B) Repeat A) until all gaps are resolved.


C) Copy any other missing archived redo log files.

SQL> SELECT UNIQUE THREAD# AS THREAD, MAX(SEQUENCE#)
2> OVER (PARTITION BY thread#) AS LAST from V$ARCHIVED_LOG;
THREAD LAST
---------- ----------
1 100

ALTER DATABASE REGISTER PHYSICAL LOGFILE 'filespec1';

now initiate failover at standby

1. ALTER DATABASE RECOVER MANAGED STANDBY DATABASE FINISH FORCE;

2. ALTER DATABASE COMMIT TO SWITCHOVER TO PRIMARY;

3. alter database open [if db opened read only since last time it was started]
else shutdown and restart