Oracle ASM: How to Create and Modify Disk Group

How to Create and Modify Disk Group

1.       Create New Disk Group

create diskgroup DATA external redundancy disk '/dev/oracleasm/disks/ASMDATA01'

ATTRIBUTE 'compatible.rdbms' = '11.1', 'compatible.asm' = '11.1';

alter diskgroup DATA check all;

If RAC then on second ASM Instance (Example ASM2):

alter diskgroup DATA mount;

2.       Add new disk in exiting diskgroup

alter diskgroup DATA add disk '/dev/oracleasm/disks/ASMDATA02';

3.       Add several disks with a wildcard:

alter diskgroup DATA add disk '/dev/oracleasm/disks/ASMDATA*';

4.       Remove a disk from a diskgroup:

alter diskgroup DATA drop disk 'DATA_0001';

5.       Drop the entire DiskGroup

drop diskgroup DATA including contents;

6.       How to DROP the entire DiskGroup when it is in NOMOUNT Status

Generate the dd command which will reset the header of all the disks belong the GROUP_NUMBER=0!!!!

select 'dd if=/dev/zero of=''' ||PATH||''' bs=8192 count=100' from v$asm_disk

where GROUP_NUMBER=0;

select * from v$asm_operation;

7. After adding new disk or dropping an existing disk, rebalance the data across the all disks by below command.

alter diskgroup DATA rebalance power 10;

--When a new diskgroup is created, it is only mounted on the local instance,

--and only the instance-specific entry for the asm_diskgroups parameter is updated.

--By manually mounting the diskgroup on other instances, the asm_diskgroups parameter

--on those instances are updated.

--on +ASM1 :

create diskgroup FRA1 external redundancy disk '/dev/vx/rdsk/fradg/fra1'

ATTRIBUTE 'compatible.rdbms' = '11.1', 'compatible.asm' = '11.1';

--on +ASM2 :

alter diskgroup FRA1 mount;