Fast-Start Failover Enable the Broker (DGMGRL) in Oracle 19C

  • Fast-Start Failover enables the broker to perform these tasks automatically failover to standby database.
  • The key to this feature is a monitoring process appropriately named the Observer. 
  • The Observer is a component of the DGMGRL interface that is configured on a system outside the systems actually running the Oracle Data Guard configuration, which monitors the availability of the primary database. 
  • It will issue a failover after waiting the number of seconds specified by the FastStartFailoverThreshold property

Fast-start failover can be enabled for either maximum availability mode or maximum performance mode

DGMGRL> EDIT CONFIGURATION SET PROTECTION MODE AS MAXAVAILABILITY;

Enable the Fast-start Failover:

DGMGRL> enable fast_start failover;

The observe-only mode for fast-start failover enables you to test how fast-start failover will
work in your environment with no impact on your current configuration or on applications:

DGMGRL> enable fast_start failover observe only;

Set FSFO targets and start the Observer:

DGMGRL> show database pearl FastStartFailoverTarget;
  FastStartFailoverTarget = ''
 
DGMGRL> edit database pearl set property FastStartFailoverTarget='muthu';
Property "faststartfailovertarget" updated
 
DGMGRL> show database pearl FastStartFailoverTarget;
  FastStartFailoverTarget = 'muthu'

# then, the other way arround in case of a role switch

DGMGRL> edit database muthu set property FastStartFailoverTarget='pearl';
Property "faststartfailovertarget" updated

Start the DGMGRL Observer:

DGMGRL> start observer;

(OR)

DGMGRL> start observer observ file is /home/opc/fsfo.dat logfile is /home/opc/observ.log;

[W000 2019-10-26T23:38:06.076+05:30] FSFO target standby is muthu
Observer 'observ' started
[W000 2019-10-26T23:38:06.983+05:30] Observer trace level is set to USER
[W000 2019-10-26T23:38:06.983+05:30] Try to connect to the primary.
[W000 2019-10-26T23:38:06.983+05:30] Try to connect to the primary pearl.
[W000 2019-10-26T23:38:07.030+05:30] The standby muthu is ready to be a FSFO target
[W000 2019-10-26T23:38:08.030+05:30] Connection to the primary restored!
[W000 2019-10-26T23:38:10.046+05:30] Disconnecting from database pearl.

The session will seem to hang. You can do a control C. Or create and run the script as nohup. (other way to start the observer)

Other way to start in background

nohup dgmgrl sys/admin123@orcl "start observer file='/home/oracle/fsfo.dat'" -logfile $HOME/observer.log &

dgmgrl SYS/admin123@pearl "start observer observ file is /home/opc/fsfo.dat logfile is home/opc/observ.log;" &

Check the observer:

DGMGRL> show observer

check the fast start failover status

DGMGRL> show fast_start failover

DGMGRL> show configuration FastStartFailoverAutoReinstate
  FastStartFailoverAutoReinstate = 'TRUE'
 
DGMGRL> show configuration FastStartFailoverThreshold
  FastStartFailoverThreshold = '30'
 
DGMGRL> edit configuration set property FastStartFailoverThreshold=15;
Property "faststartfailoverthreshold" updated

Disable the Fast-Start Failover (FSFO);

DGMGRL> DISABLE FAST_START FAILOVER;

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