OCP-1Z0-053-V12.02-156题

 

156.What is the effect of increasing the value of the ASM_POWER_LIMIT parameter?

A. The number of DBWR processes increases

B. The number of ASMB processes increases

C. The number of DBWR_TO_SLAVES increases

D. The rebalancing operation in an ASM instance completes more quickly, but can result in higher I/O

overhead

Answer: D

答案解析：

参考：http://blog.csdn.net/rlhua/article/details/12972983

• ASM_POWER_LIMIT控制重新平衡操作的速度。值的范围从1 到11，11 表示最快。如果省略，该值默认为1。

ASM_POWER_LIMIT

The ASM_POWER_LIMIT initialization parameter specifies the default power for disk rebalancing in a disk group. The range of values is 0 to 1024. The default value is 1. A value of 0 disables rebalancing. Higher numeric values enable the rebalancing operation to complete more quickly, but might result in higher I/O overhead and more rebalancing processes.

• For disk groups that have the disk group ASM compatibility set to 11.2.0.2 or greater (for example, COMPATIBLE.ASM = 11.2.0.2), the operational range of values is 0 to 1024 for the rebalance power.

• For disk groups that have the disk group ASM compatibility set to less than 11.2.0.2, the operational range of values is 0 to 11 inclusive. If the value forASM_POWER_LIMIT is larger than 11, a value of 11 is used for these disk groups.

You can also specify the power of the rebalancing operation in a disk group with the POWER clause of the SQL ALTER DISKGROUP ... REBALANCE statement. The range of allowable values for the POWER clause is the same for the ASM_POWER_LIMIT initialization parameter. If the value of the POWER clause is specified larger than 11 for a disk group with ASM compatibility set to less than 11.2.0.2, then a warning is displayed and a POWER value equal to 11 is used for rebalancing.

官方参考：http://docs.oracle.com/cd/E11882_01/server.112/e18951/asminst.htm#OSTMG10144