Adding Disks to a Disk Group
ALTER DISKGROUP DATA_DG ADD DISK '/devices/DiskA1’,’/device/DiskB1';
Dropping Disks and Disk Groups
ALTER DISKGROUP DATA_DG DROP DISK DiskA1;
DROP DISKGROUP DATA_DG INCLUDING CONTENTS;
Note:
· DROP DISKGROUP statements requires the instance to be in MOUNT state.
Rebalance Disk Group
· ASM rebalance a disk group automatically, whenever we add or remove disks form disk group.
· Disk groups can be rebalanced manually using the REBALANCE clause of the ALTER DISKGROUP statement.
· If the POWER clause is omitted the ASM_POWER_LIMIT parameter value is used.
Example :
SQL> ALTER DISKGROUP DATA_DG REBALANCE POWER 5; [By Default is 1]
SQL> select * from v$asm_operation;
GROUP_NUMBER OPERA STAT POWER ACTUAL SOFAR EST_WORK EST_RATE
------------ ----- ---- ---------- ---------- ---------- ---------- ----------
1 REBAL WAIT 5 0 0 0