Examine the Data Guard configuration:
DGMGRL> show configuration verbose;
Configuration –Animals
Protection Mode: MaxPerformance
Databases:
cats- Primary database
dogs-(*) Physical standby database
sheep- Physical standby database
(*) Fast-Start Failover target
Properties:
FastStartFailoverThreshold = ‘30’
OperationTimeout = ‘30’
TraceLevel = ‘USER’
FastStartFailoverLagLimit = ‘30’
CommunicationTimeout= ‘180’
ObserverReconnect= ‘10’
FastStartFailoverAutoReinstate= ‘FALSE’
FastStartFailoverPmyShutdown= ‘TRUE’
BystanderFollowRoleChange= ‘none’
ObserverOverride = ‘FALSE’
Fast-Start Failover: ENABLED
Threshold: 30 seconds
Target: dogs
Observer: 015.example.com
Lag Limit: 30 seconds
Shutdown Primary: TRUE
Auto-reinstate: FALSE
Observer Reconnect: 10 seconds
Observer Override: TRUE
Configuration Status:
SUCCESS
Which two are true?
A.
The observer must run on host ol5.example.com and is currently not running.
B.
The observer will reinstate Sheep automatically after a failover, if required.
C.
The observer will mark another standby database as the failover target if the original failover target becomes unavailable.
D.
The observer will detect if the primary database is unable to accept new connections.
E.
The former primary database will not be reinstated automatically after a failover.
Explanation:
B: . If fast-start failover is enabled, the observer will automatically reinstate the standby databases after failover has completed.
E: FastStartFailoverAutoReinstate= ‘FALSE’ means that the former primary database will not be reinstated automatically after a failover,
Note: The FastStartFailoverAutoReinstate configuration property causes the former primary database to be automatically reinstated if a fast-start failover was
initiated because the primary database was either isolated or had crashed. To prevent automatic reinstatement of the former primary database in these cases, set
this configuration property to FALSE.
The observer is the third party in an otherwise typical primary/standby Data Guard configuration. Only the observer can initiate FSFO failover. It’s secondary job is
to automatically reinstate a failed primary as a standby if that feature is enabled (the default).
Incorrect Answers:
A: The observer is running.
B: Sheep is neither the primary database, nor the failover target.
D: By default, the observer will initiate failover to the target standby if and only if ALL of the following are true:
* observer is running
* observer and the standby both lose contact with the primary
Note: if the observer loses contact with the primary, but the standby does not, the observer can determine that the primary is still up via the standby.
* observer is still in contact with the standby
* durability constraints are met
* failover threshold timeout has elapsedhttp://www.oracle.com/technetwork/articles/smiley-fsfo-084973.html
https://docs.oracle.com/cd/E11882_01/server.112/e40771/dbpropref.htm
Not B. SHEEP is a bystander in the failover. “BystandersFollowRoleChange=NONE” means that all bystanders will be disabled (see https://docs.oracle.com/database/121/DGBKR/dbpropref.htm#DGBKR3436).
D,E
Observer Override: TRUE (although first It states the oposite, it is a bit ambiguous)
It means that observer can initiate a FFO if cannot comunicate w/ Primary.
CommunicationTimeout= ‘180’
ObserverReconnect= ‘10’
It means that observer is continuosly connecting to Primary to check if connetion it possible and do a FFO if not.
B is correct:
NONE – During the failover process, the broker does NOT evaluate the status of the bystander standbys as part of the failover operation. They are marked as disabled with a status of ORA-16661 so that they can be evaluated later. The broker simply completes the failover to produce a new primary database as soon as possible.
The NONE option decreases the processing time for failover, but disables broker management of all bystander databases in the configuration. If fast-start failover is enabled, then the observer automatically reinstates the standby databases after failover has completed. Otherwise, you will have to manually reinstate the standby databases after failover has completed.
B,E
Seems D, E
The BystandersFollowRoleChange configuration property establishes whether bystander standby databases are evaluated during failover (value = ALL) or after failover (value = NONE).
• ALL – During the failover process, the broker determines whether the bystander standby databases are ahead of or behind the failover target standby (that is, the standby that will be the new primary).
If the bystander standbys are ahead, they will be disabled with a status of ORA-16661 as part of the failover operation. The bystander standbys must be reinstated after failover completes. The broker reinstates a standby through a flashback to the SCN at which the target standby became a primary database, and sets up the redo transport configuration from the new primary to the standby.
If the bystander standbys are behind, then the broker simply sets up the redo transport configuration from the soon-to-be-new-primary to these standbys and completes the failover process.
• NONE – During the failover process, the broker does NOT evaluate the status of the bystander standbys as part of the failover operation. They are marked as disabled with a status of ORA-16661 so that they can be evaluated later. The broker simply completes the failover to produce a new primary database as soon as possible.
After the failover is completed, you can reinstate the bystander standbys. During reinstatement of a bystander, the broker determines whether the bystander is ahead of, or behind, the new primary. If the bystander is ahead of the new primary, then the broker automatically flashes back the standby to the SCN at which the target standby became a primary database and sets up redo transport from the new primary to the standby. (Even if a flashback is not required, the broker sets up the redo transport configuration from the new primary to these standbys.)
The NONE option decreases the processing time for failover, but disables broker management of all bystander databases in the configuration. If fast-start failover is enabled, then the observer automatically reinstates the standby databases after failover has completed. Otherwise, you will have to manually reinstate the standby databases after failover has completed.