Add/Drop ASM disks to DISKGROUP on RAC(or Standalone)

Note: The steps are described for RAC, but you can easily guess what are the steps for the standalone database.

1. First of all find the disk or partition name, that should be added to the ASM.

fdisk -l

My disk partition name is /dev/sdi1.

2. Assign the disk to ORACLEASM.

–On node1

/etc/init.d/oracleasm createdisk DISK7 /dev/sdi1

3. Scan disks in ALL NODES and list them to check if is presented.

–On node1

/etc/init.d/oracleasm scandisks
/etc/init.d/oracleasm listdisks

–On node2

/etc/init.d/oracleasm scandisks
/etc/init.d/oracleasm listdisks

4. Change the environment to the grid infrastructure, by setting ORACLE_SID to +ASM and so on :

$ . oraenv
ORACLE_SID = [media1] ? +ASM1
The Oracle base for ORACLE_HOME=/u01/app/11.2.0/grid is /u01/app/oracle

# Connect as an SYSASM

sqlplus / as sysasm

Note: If you don’t remember the password for the sysasm user see How to reset SYSASM password.

# Find the diskgroup name

SQL> select name from v$asm_diskgroup;

NAME
——————————
DATA01

# Increase power limit, if you want, to complete rebalance operation in a short time.

SQL>  alter system set asm_power_limit=10

# Indicate disks location by the parameter asm_diskstring

SQL> alter system set asm_diskstring=’ORCL:DISK*’

SQL> alter diskgroup DATA01 add disk ‘ORCL:DISK7’;

It will do the rebalance automatically.

# To drop the disk , do the following:

SQL >  alter diskgroup DATA01 drop disk DISK7;

It will rebalance first and then drops the disk automatically.

You can see the current operation in v$asm_operation view.

Note: Until the view v$asm_operation contains a record you are able to undrop the disks by the following way:

SQL> alter diskgroup DATA01 undrop disks;

If the operation is already completed , you are not able to undrop the disk . But you can re-add the disk , if you want.

That is all.