Dataguard Switchover Using DGMGRL
A switchover is a role reversal between the primary database and one of its standby databases. A switchover guarantees no data loss.
This is typically done for planned maintenance of the primary system.
During a switchover, the primary database transitions to a standby role and the standby database transitions to the primary role
The role of the primary database and a standby database is going to change using the SWITCHOVER command
The broker configuration file is updated to reflect the change in roles.
| DETAILS | SOURCE | TARGET |
| IP_ADDRESS | 192.168.1.44 | 192.168.1.37 |
| SERVER_NAME | PRIMARY | STANDBY |
| DB_VERSION | 19.3.0.0 | 19.3.0.0 |
| DB_NAME | PROD | STANDBY |
CHECK THE DATABASE STATUS :
DGMGRL> show configuration
Configuration – sathish
Protection Mode: MaxPerformance
Members:
PROD – Primary database
STANDBY – Physical standby database
Fast-Start Failover: Disabled
Configuration Status:
SUCCESS (status updated 42 seconds ago)
Check the Database Is Ready for a Role Change
It will checks whether it is ready for switchover.
DGMGRL> VALIDATE DATABASE ‘prod’;
Database Role: Primary database
Ready for Switchover: Yes
Flashback Database Status:
prime: Off
DGMGRL> VALIDATE DATABASE ‘standby’;
Database Role: Physical standby database
Primary Database: prime
Ready for Switchover: Yes
Ready for Failover: Yes (Primary Running)
Flashback Database Status:
prime: Off
stand: Off
PERFORM THE SWITCHOVER OPERATION :
DGMGRL> switchover to standby;
Performing switchover NOW, please wait…
Operation requires a connection to database “STANDBY”
Connecting …
Connected to “STANDBY”
Connected as SYSDBA.
New primary database “STANDBY” is opening…
Operation requires start up of instance “prod” on database “BALL”
Starting instance “prod”…
Connected to an idle instance.
ORACLE instance started.
Connected to “PROD”
Database mounted.
Connected to “PROD”
Switchover succeeded, new primary is “standby”
DGMGRL>
CHECK THE STATUS IN DG_BROKER :
DGMGRL> show configuration
Configuration – sathish
Protection Mode: MaxPerformance
Members:
STANDBY – Primary database
PROD – Physical standby database
Fast-Start Failover: Disabled
Configuration Status:
SUCCESS (status updated 21 seconds ago)
VERIFY THE STATUS :
DGMGRL> show database ‘PROD‘;
Database – PROD
Role: PHYSICAL STANDBY
Intended State: APPLY-ON
Transport Lag: 0 seconds (computed 0 seconds ago)
Apply Lag: 0 seconds (computed 0 seconds ago)
Average Apply Rate: 7.00 KByte/s
Real Time Query: OFF
Instance(s):
PROD
Database Status:
SUCCESS
DGMGRL> SHOW DATABASE ‘STANDBY‘;
Database – STANDBY
Role: PRIMARY
Intended State: TRANSPORT-ON
Instance(s):
PROD
Database Status:
SUCCESS
