SWITCHOVER and SWITCHBACK in Data guard

Switching Over to a Physical Standby Database

SWITCHOVER STEPS:-

PRIMARY
-------
check DR SYNC STATUS
http://select-star-from.blogspot.in/2013/09/data-guard-sync-status.html

SQL>archive log list
SQL>select name,instance_name,open_mode,database_role,switchover_status from v$database,v$instance;
SQL>alter database commit to switchover to physical standby with session shutdown;
SQL>shutdown immediate
SQL>startup nomount
SQL>alter database mount standby database;
SQL>alter system set log_archive_dest_state_2=defer scope=both;
SQL>select name,open_mode,database_role,switchover_status from v$database;
SQL>show parameter log_archive_dest_state_2;

STANDBY
-------
SQL>archive log list
SQL>select name,instance_name,open_mode,database_role,switchover_status from v$database,v$instance;
SQL>alter database commit to switchover to primary;
SQL>shutdown immediate
SQL>startup

OLD PRIMARY ----->New STANDBY
-----------
SQL>select name,instance_name,open_mode,database_role,switchover_status from v$database,v$instance;
SQL>recover managed standby database disconnect;
SQL>select process,status,sequence# from v$managed_standby;

OLD STANDBY ----->New PRIMARY
-----------
SQL>select name,instance_name,open_mode,database_role,switchover_status from v$database,v$instance;
SQL>show parameter log_archive_dest_state_2;
SQL>alter system set log_archive_dest_state_2=enable scope=both;
SQL>alter system switch logfile;
SQL>alter system switch logfile;
SQL>alter system switch logfile;
SQL>alter system switch logfile;
SQL>select status, gap_status from v$archive_dest_status where dest_id = 2;  --------11gr2 onwards

check DR SYNC STATUS
http://select-star-from.blogspot.in/2013/09/data-guard-sync-status.html

SWITCHBACK STEPS:-

OLD STANDBY ----->New PRIMARY
-----------
check DR SYNC STATUS
http://select-star-from.blogspot.in/2013/09/data-guard-sync-status.html

SQL>archive log list
SQL>select name,instance_name,open_mode,database_role,switchover_status from v$database,v$instance;
SQL>alter database commit to switchover to physical standby with session shutdown;
SQL>shutdown immediate
SQL>startup nomount
SQL>alter database mount standby database;
SQL>alter system set log_archive_dest_state_2=defer scope=both;
SQL>select name,open_mode,database_role,switchover_status from v$database;
SQL>show parameter log_archive_dest_state_2;

OLD PRIMARY ----->New STANDBY
-----------
SQL>archive log list
SQL>select name,instance_name,open_mode,database_role,switchover_status from v$database,v$instance;
SQL>alter database commit to switchover to primary;
SQL>shutdown immediate
SQL>startup

OLD STANDBY ----->New PRIMARY ----->ORIGINAL STANDBY
-----------
SQL>select name,instance_name,open_mode,database_role,switchover_status from v$database,v$instance;
SQL>recover managed standby database disconnect;
SQL>select process,status,sequence# from v$managed_standby;

OLD PRIMARY ----->New STANDBY ----->ORIGINAL STANDBY
-----------
SQL>select name,instance_name,open_mode,database_role,switchover_status from v$database,v$instance;
SQL>show parameter log_archive_dest_state_2;
SQL>alter system set log_archive_dest_state_2=enable scope=both;
SQL>alter system switch logfile;
SQL>alter system switch logfile;
SQL>alter system switch logfile;
SQL>select status, gap_status from v$archive_dest_status where dest_id = 2; --------11gr2 onwards

check DR SYNC STATUS
http://select-star-from.blogspot.in/2013/09/data-guard-sync-status.html

SOURCE : Internet

Reference(s):
http://emrebaransel.blogspot.in/2008/08/dataguard-switchover-guide-physical_09.html
http://subhendrasahu.blogspot.in/2012/05/switchover-from-primaryto-standby.html

http://shivanandarao.wordpress.com/2012/08/28/dataguard-failover/