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Failover Activity Use Dataguard Broker (DGMGRL) in Oracle 19C

Failover Activity:

(crashed the Primary database and make standby database to primary role)

Step 1. Crash or down the  primary:

ps -ef|grep pmon

oracle   16914     1  0 14:03 ?        00:00:00 ora_pmon_pearl
oracle   17722 15893  0 15:08 pts/0    00:00:00 grep pmon

kill -9 16914

(OR)

shutdown the primary database (shut immediate)

alter system switch logfile;
shut immediate

Step 2. Run Failover Command in Standby:

DGMGRL> dgmgrl sys/sys@muthu

DGMGRL> show configuration;

DGMGRL> FAILOVER TO muthu;

Performing failover NOW, please wait...
Failover succeeded, new primary is "muthu"

DGMGRL> show configuration;

Step 3.Rebuild Old Primary After Failover:

Post failover, there are two methods of rebuilding your failed primary

Method 1: Rebuild from scratch –> RMAN duplicate

Method 2: Flashback database –> only if Flashback was enabled

Reinstate failed primary: When you use data guard broker, with just one command, the primary can be rebuilt. Start the failed primary server, in this case start pearl server

start the old primary with mount stage

startup mount

On current primary (muthu):

DGMGRL> dgmgrl sys/sys@muthu

DGMGRL> show configuration;
DGMGRL> reinstate database pearl;
Reinstating database "pearl", please wait...
Operation requires shutdown of instance "pearl" on database "pearl"
Shutting down instance "pearl"...ORA-01109: database not open

Database dismounted.ORACLE instance shut down.
Operation requires startup of instance "pearl" on database "pearl"
Starting instance "pearl"...ORACLE instance started.
Database mounted.
Continuing to reinstate database "pearl" ...
Reinstatement of database "pearl" succeeded

Verify pearl post reinstate: The best part is broker will automatically recover earlier failed primary pearl, mount the database and start MRP too

On failed primary (pearl):

select name,open_mode from v$database;
select process, status, sequence# from v$managed_standby;

Switchover to get original configuration (Revert Back): At this stage, you can perform switchover to again get back original configuration

On current primary (muthu):

dgmgrl sys/sys@muthu
DGMGRL> switchover to pearl;

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