OCP-043 alter diskgroup power

67. You are using an Automatic Storage Management (ASM) instance to manage the database files of
your production database. After adding a new disk group to the ASM instance, you execute the following
command:
ALTER DISKGROUP dg3 REBALANCE POWER 0;
What would be the result of this command?
A.The rebalancing of the disk group would be stopped.
B.The rebalancing of the disk group would be completed as fast as possible.
C.The command would result in an error because the value of POWER cannot be 0.
D.The rebalancing of the disk group would be completed without affecting the disk group DG3.
E.The command would result in an error because the disk groups cannot be manually rebalanced.
Answer: A

diskgroup_clauses

Use these clauses to operate on entire disk groups.

rebalance_diskgroup_clause

Use this clause to manually rebalance the disk group. Automatic Storage Management redistributes datafiles evenly across all drives. This clause is rarely necessary, because Automatic Storage Management allocates files evenly and automatically rebalances diskgroups when the storage configuration changes. However, it is useful if you want to use the POWER clause to control the speed of what would otherwise be an automatic rebalance operation.

POWER In the POWER clause, specify a value from 0 to 11, where 0 stops the rebalance operation and 11 permits Automatic Storage Management to execute the rebalance as fast as possible. The value you specify in the POWER clause defaults to the value of the ASM_POWER_LIMIT initialization parameter.

If you omit the POWER clause, then Automatic Storage Management executes both automatic and specified rebalance operations at the power determined by the value of the ASM_POWER_LIMIT initialization parameter.

WAIT | NOWAIT Use this clause to specify when in the course of the rebalance operation control should be returned to the user.

• Specify WAIT to allow a script that adds or removes disks to wait for the disk group to be rebalanced before returning control to the user. You can explicitly terminate a rebalance operation running in WAIT mode, although doing so does not undo any completed disk add or drop operation in the same statement.

• Specify NOWAIT if you want control returned to the user immediately after the statement is issued. This is the default.

You can monitor the progress of the rebalance operation by querying the V$ASM_OPERATION dynamic performance view.