Note: Adding new disks to diskgroup invokes implicit rebalancing of all the disks within the diskgroup.

Instance: ASM Instance
Privilege: Sysdba

Syntax

ALTER DISKGROUP diskgroup_name ADD [FAILGROUP failgroup_name] DISK add_disk_clause rebalance_diskgroup_clause

Where

Add_disk_clause = search_string [NAME disk_name] [SIZE size_clause] [FORCE/NOFORCE]
Force – Add disk to the diskgroup even if the disk is part of some other diskgroup.
NoForce – ASM returns error if the disk is part of some other diskgroup.

Rebalance_diskgroup_clause = REBALANCE POWER integer WAIT/NOWAIT
Integer – 0 to 11. If you omit ASM takes the value from ASM_POWER_LIMIT init parameter.
WAIT – The control is not returned to the user until the rebalance operation completes.
NOWAIT – The control immediately returns to the user and the rebalance operation takes place at the background and user can continue to do other operation.

Example 1

SQL> Alter Diskgroup ASMDATA ADD
FAILGROUP ctrl_1
DISK
'/u01/asmdisks/disk1' NAME data_05 NOFORCE,
'/u01/asmdisks/disk2' NAME data_06 NOFORCE;

Example 2

SQL> Alter Diskgroup ASMIND ADD
DISK '/dev/rhdisk33'
REBALANCE POWER 5 ;

Thanks