SWITCHOVER and SWITCHBACK in Data guard

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/

In RAC Environment

Hi Guys,

Today I performed RAC Switchover / Switchback for 2 Node Primary with 2 Node Standby on OEL. I expected some issues, but it was totally smooth. Giving you steps for the same, so it will be useful to you. Even this would be my first contribution to 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
or
sql>shutdown immediate
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
or
sql>shutdown immediate;

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 & Failover.