Add,drop and rebalance ASM diskgroups

Introduction

Steps to see how we can add, drop and rebalance diskgroups

Posted by Karthick

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