You administer a six-instance, policy-managed, multitenant RAC database CDB1 with three PDBs: PDB_1, PDB_2 and PDB_3.
Server pool prod_pool has a cardinality of three and all six hosts of the cluster app.
Examine these commands executed on HOST01:
$ srvctl add service –db CDB1 –pdb PDB_1 service AR –serverpool prod_pool –cardinality singleton
$ srvctl start service –db CDB1 –service AR
Which two statements are true regarding the AR service?
A.
AR runs as a singleton service in the server pool prod_pool and the AR service is available in each of the CDB1 instances.
B.
AR is available on any one available CDB1 instance in prod_pool at any one time.
C.
AR can fail over to any one of the available CDB1 instances.
D.
AR is available only on the CDB1 instance on HOST01.
E.
AR can fail over to any other available CDB1 instance in prod_pool.
Explanation:
A,B,E WRONG
When you define services for a policy-managed database you assign the service to a server pool in which the database is hosted using SRVCTL with the -serverpool parameter.
You can define the service as either UNIFORM (running on all instances in the server pool) or SIGLETON (running on only one instance in the server pool)using -cardinality parameter. For singleton services oracle RAC chooses on which instance in the server pool the service is active, if that instance fails, then the service fails over to another instance in the server pool. A service can only run in one server pool and oracle recommends that every server pool has at least one service.
C,D correct
sorry C,E correct
E: because if that instance fails then the service fails over to another instance in the server pool and the service can only run in one server pool not in HOST01 only
the correct is C & E
I don’t think C is correct: the AR service can only fail over to an instance in the prod_pool serverpool, so E is correct and C isn’t.
The other correct answer is B, since the service is singleton.
This is a problem with the english to me! I speak portuguese and in my traduction, i understand that “the service will be available in every one instance that is available at any time”. And this is not true! This is a singleton service and it will be available in only one available instance!
Can you help me?! I’m wrong?!
B,E
B – because the AR service is running within prod_pool only, thus “C” – answer is not correct since it refers to entire CDB1.
E is correct by same reason: refers to the service behavior within prod_pool.
B,E
the database CBD1 could belong to a even bigger server pool, in that Case C is incorrect.