How to rebalance an ASM disk group and set the power in Oracle

Manually rebalance a disk group or change the speed of a rebalance already running. Higher power is faster but uses more I/O. Run connected to the ASM instance AS SYSASM.

A higher power consumes more I/O and can affect database performance; a power of 0 stops the rebalance. Valid values are 0 to 11 (up to 1024 with ASM compatibility 11.2.0.2 and higher).

-- Start or adjust a rebalance
ALTER DISKGROUP &&dg_name REBALANCE POWER 6;

-- Stop it:
-- ALTER DISKGROUP &dg_name REBALANCE POWER 0;

-- Or wait for it to finish:
-- ALTER DISKGROUP &dg_name REBALANCE WAIT;

-- Verify (read-only)
SELECT operation, state, power, sofar, est_work, est_minutes
FROM   v$asm_operation
WHERE  group_number = (SELECT group_number FROM v$asm_diskgroup
                       WHERE name = UPPER('&dg_name'));