Oracle Database ASM Features: REBALANCING

ASM has the ability to rebalance data across the disks whenever a disk is added,dropped or replaced.
The performance of rebalance operation is controlled by initialization parameter ASM_POWER_LIMIT.

ASM_POWER_LIMIT Parameter

Default value 1

Range of Values 0 to 11 (Prior to 11gR2)

Range of Values 0 to 1024(From 11gR2)

For 10g Databases:

SQL> alter diskgroup DG1 rebalance power 12;
alter diskgroup DG1 rebalance power 12
                                              *
ERROR at line 1:
ORA-15102: invalid POWER expression

SQL> alter diskgroup DG1 rebalance power 11;

Diskgroup altered.


For 11g AND 12c Databases

SQL> alter diskgroup DG1 rebalance power 1025;
alter diskgroup DG1 rebalance power 1025
                                      *
ERROR at line 1:
ORA-15102: invalid POWER expression

SQL> alter diskgroup DG1 rebalance power 1024;

Diskgroup altered.

The higher the value of rebalancing power, faster would be rebalancing operation.