RAC Switchover / Switchback

RAC Switchover / Switchback for 2 Node Primary with 2 Node Standby. Got from oracle forums.
DB Name DB Unique Name Host Name Instance Name

--------------------------------------------------------------------------------
live live linux1 live1
live live linux2 live2
live livestdby linux3 livestdby1
live livestdby linux4 livestdby2

Verify that each database is properly configured for the role it is about to assume and the standby database is in mounted state.
(Verify all Dataguard parameters on each node for Primary & Standby)

Like,
Log_archive_dest_1
Log_archive_dest_2
Log_archive_dest_state_1
Log_archive_dest_state_2
Fal_client
Fal_server
Local_listener
Remote_listener
Standby_archive_Dest
Standby_archive_management
service_names
db_unique_name
instance_name
db_file_name_convert
log_file_name_convert

Verify that both Primary RAC & Dataguard RAC are functioning properly and both are in Sync
On Primary,
Select thread#,max(sequence#) from v$archived_log group by thread#;
On Standby,
Select thread#,max(sequence#) from v$log_history group by thread#;

Before performing a switchover from a RAC primary shut down all but one primary instance (they can be restarted after the switchover has completed).
./srvctl stop instance –d live –i live1
Before performing a switchover or a failover to a RAC standby shut down all but one standby instance (they can be restarted after the role transition has completed).
./srvctl stop instance –d live –i livestdby1

On the primary database initiate the switchover:
alter database commit to switchover to physical standby with session shutdown;
Shutdown former Primary database & Startup in Mount State.
Shut immediate;
Startup mount;
select name,db_unique_name, log_mode,open_mode,controlfile_type,switchover_status,database_role from v$database;

Make log_Archive_Dest_state_2 to DEFER
alter system set log_archive_dest_state_2='DEFER' sid='*';

On the (old) standby database,
select name,log_mode,open_mode,controlfile_type,switchover_status,database_role from v$database;

On the (old) standby database switch to new primary role:
alter database commit to switchover to primary;
shut immediate;
startup;

On new Primary database,
select name,log_mode,open_mode,controlfile_type,switchover_status,database_role from v$database;
Make log_Archive_Dest_state_2 to ENABLE
alter system set log_archive_dest_state_2='ENABLE' sid='*';
Add tempfiles in New Primary database.
Do some archivelog switches on new primary database & verify that archives are getting transferred to Standby database.

On new primary,
select error from v$archive_Dest_status;
select max(sequence#) from v$archived_log;

On new Standby, Start Redo Apply

alter database recover managed standby database using current logfile disconnect;

Select max(sequence#) from v$log_history; (should be matching with Primary)



Now Start RAC databases services (both Primary – in open & Standby – in mount)
On new Primary Server.
./srvctl start instance –d live –i livestdby2
Verify using ./crs_stat –t
Check that database is opened in R/W mode.
On new Standby Server.
./srvctl start instance –d live –i live2 –o mount

Now add TAF services on new Primary (former Standby) Server.
By Command Prompt,
./srvctl add service -d live -s srvc_livestdby -r livestdby1,livestdby2 -P BASIC
OR
By GUI,
dbca -> Oracle Read Application Cluster database -> Service Management -> select database -> add services, details (Preferred / Available), TAF Policy (Basic / Preconnect) - > Finish

Start the services,
./srvctl start service -d live

Verify the same,
./crs_stat -t

Perform TAF testing, to make sure Load Balancing