Examine the Data Guard configuration:
DGMGRL> show configuration;
Configuration –Animals
Protection Mode: MaxAvailability
Databases:
dogs- Primary database
cats- Snapshot standby database
sheep- Snapshot standby database
Fast-Start Failover: DISABLED
Configuration Status:
ORA-01034: ORACLE not available
ORA-16625: cannot reach database “dogs”
DGM-17017: unable to determine configuration status
You wish to perform a failover to Sheep.
Which command, or sequence of commands, should you issue to the broker before executing “failover to
sheep”, using the broker?
A.
DGMGRL> convert database cats to physical standby;
B.
DGMGRL> convert database sheep to physical standby;
C.
DGMGRL> convert database sheep to physical standby;
DGMGRL> convert database cats to physical standby;
D.
DGMGRL>edit configuration set protection mode as maxperformance;
DGMGRL> convert database sheep to physical standby;
E.
None, because you can directly failover to a Snapshot Standby Database.
Explanation:
Note: Oracle Error: ORA-16625
Error Description:
Cannot reach the database
Error Cause:
The broker rejected an operation requested by the client when the database required to execute that operation
was not reachable from the database where the request was made. If the request modifies the configuration,
the request must be processed by the copy of the broker running on an instance of the primary database.
Action:
Check your network connections between all of the databases in the configuration. Alternatively, you can
connect your client to a different database in the Data Guard broker configuration and try your request again. If
you are simply attempting to determine the status of a particular database in the configuration, you may
connect your client to that database and get the current value of the StatusReport property for that database.
http://psoug.org/oraerror/ORA-16625.htm
Correct Ans: E (though it sounds stupid)
A, B, C, D are all incorrect
Because in order to issue CONVERT or EDIT CONFIGURATION commands, broker must communicate to the Primary database “dogs” which is currently not available.
In a non-Broker configuration, you must convert the snapshot standby database to physical standby using manual methods.
Here Data Guard Broker is used so you can directly failover to a Snapshot Standby Database and it will perform the failover to “Sheep”. Once the failover is complete you must reinstate old primary database “dogs” by 1) startup mount “dogs”, 2) Connect to new primary database “Sheep” and issue “reinstate database dogs”. You might need to change the protection mode afterwards, if required if the LogXptMode was not set originally otherwise it will report a Warning, however, data guard will function as expected.
DGMGRL> show configuration;
Configuration – Animals
Protection Mode: MaxAvailability
Members:
dogs – Primary database
Error: ORA-01034: ORACLE not available
cats – Snapshot standby database
sheep – Snapshot standby database
Fast-Start Failover: DISABLED
Configuration Status:
ERROR (status updated 0 seconds ago)
DGMGRL> convert database cats to physical standby;
Converting database “cats” to a Physical Standby database, please wait…
Error: ORA-01034: ORACLE not available
Error: ORA-16625: cannot reach database “dogs”
Failed.
Failed to convert database “cats”
DGMGRL> convert database sheep to physical standby;
Converting database “sheep” to a Physical Standby database, please wait…
Error: ORA-01034: ORACLE not available
Error: ORA-16625: cannot reach database “dogs”
Failed.
Failed to convert database “sheep”
DGMGRL> edit configuration set protection mode as maxperformance;
Error: ORA-01034: ORACLE not available
Error: ORA-16625: cannot reach database “dogs”
Failed.
DGMGRL> failover to sheep;
Converting database “sheep” to a Physical Standby database, please wait…
Operation requires shut down of instance “sheep” on database “sheep”
Shutting down instance “sheep”…
Database closed.
Database dismounted.
ORACLE instance shut down.
Operation requires start up of instance “sheep” on database “sheep”
Starting instance “sheep”…
ORACLE instance started.
Database mounted.
Continuing to convert database “sheep” …
Database “sheep” converted successfully
Performing failover NOW, please wait…
Failover succeeded, new primary is “sheep”