Add/Remove Disks from ASM disk group on live database

ASM will allow the adding and removing of volumes from a disk group while disk group is still in use by a database. This will allow the replacement of disk volumes from olds disk to new without having to bring the database down.

Steps:

1. Find out or disk groups

SQL> select group_number, name from v$asm_diskgroup ;
GROUP_NUMBER NAME
------------ ------------------------------
1 P1CSM2_ASM_DG1

SQL>


2. Find the disk volumes that make up the ASM diskgroup that we want to work with. In this example we will be replacing the 3 old disk volumes with 3 new ones.

SQL> select disk_number, mode_status, name, path from v$asm_disk where group_number = 1 order by disk_number, name ;

DISK_NUMBER MODE_ST NAME
----------- ------- ------------------------------
PATH
-----------------------------------------------------------
0 ONLINE P1CSM2_ASM_DG1_0000
/dev/rhdisk2
1 ONLINE P1CSM2_ASM_DG1_0001
/dev/rhdisk3
2 ONLINE P1CSM2_ASM_DG1_0002
/dev/rhdisk4

SQL>

3. Make sure our new volumes can be seen by asm as our disk string will be different.

SQL> alter system set ASM_DISKSTRING='/dev/rhdisk*','/dev/rrawlv*' scope=both ;

System altered.

SQL>

4. Add new disks to our disk group

SQL> ALTER DISKGROUP P1CSM2_ASM_DG1 ADD DISK '/dev/rrawlv01' NAME P1CSM2_ASM_DG1_0010 NOFORCE ;

Diskgroup altered.

SQL> select * from v$asm_operation ;

GROUP_NUMBER OPERA STAT POWER ACTUAL SOFAR EST_WORK
------------ ----- ---- ----- ------ ----- ----------
EST_RATE EST_MINUTES
-------- -----------
1 REBAL RUN 1 1 910 1167
1577 0

SQL> select * from v$asm_operation ; no rows selected SQL> ALTER DISKGROUP P1CSM2_ASM_DG1 ADD DISK '/dev/rrawlv02' NAME P1CSM2_ASM_DG1_0011 NOFORCE ;

Diskgroup altered.

SQL> select * from v$asm_operation ;

GROUP_NUMBER OPERA STAT POWER ACTUAL SOFAR EST_WORK
------------ ----- ---- ----- ------ ----- --------
EST_RATE EST_MINUTES
-------- -----------
1 REBAL RUN 1 1 413 1881
1498 0

SQL> select * from v$asm_operation ;

no rows selected

SQL> ALTER DISKGROUP P1CSM2_ASM_DG1 ADD DISK '/dev/rrawlv03' NAME P1CSM2_ASM_DG1_0012 NOFORCE ;

Diskgroup altered.

SQL> select * from v$asm_operation ;

GROUP_NUMBER OPERA STAT POWER ACTUAL SOFAR EST_WORK
------------ ----- ---- ----- ------ ----- --------
EST_RATE EST_MINUTES
-------- -----------
1 REBAL RUN 1 1 254 1786
1514 1

SQL> select * from v$asm_operation ;

no rows selected

SQL>


5. Check that our new disk volumes are now part of our disk group.

SQL> select disk_number, mode_status, name, path from v$asm_disk where group_number = 1 order by disk_number, name ;

DISK_NUMBER MODE_ST NAME
----------- ------- ------------------------------
PATH
-----------------------------------------------------------
0 ONLINE P1CSM2_ASM_DG1_0000
/dev/rhdisk2
1 ONLINE P1CSM2_ASM_DG1_0001
/dev/rhdisk3
2 ONLINE P1CSM2_ASM_DG1_0002
/dev/rhdisk4
3 ONLINE P1CSM2_ASM_DG1_0010
/dev/rrawlv01
4 ONLINE P1CSM2_ASM_DG1_0011
/dev/rrawlv02
5 ONLINE P1CSM2_ASM_DG1_0012
/dev/rrawlv03

6 rows selected.

SQL>


6. Remove the disks we want to remove from the group
SQL> ALTER DISKGROUP P1CSM2_ASM_DG1 DROP DISK P1CSM2_ASM_DG1_0000 ;

Diskgroup altered.

SQL> select * from v$asm_operation ;

GROUP_NUMBER OPERA STAT POWER ACTUAL SOFAR EST_WORK
------------ ----- ---- ----- ------ ----- --------
EST_RATE EST_MINUTES
-------- -----------
1 REBAL RUN 1 1 548 2884
1588 1

SQL> select * from v$asm_operation ;

no rows selected

SQL> ALTER DISKGROUP P1CSM2_ASM_DG1 DROP DISK P1CSM2_ASM_DG1_0001 ;

Diskgroup altered.

SQL> select * from v$asm_operation ;

GROUP_NUMBER OPERA STAT POWER ACTUAL SOFAR EST_WORK
------------ ----- ---- ----- ------ ----- --------
EST RATE EST_MINUTES
-------- -----------
1 REBAL RUN 1 1 906 3274
1731 1


SQL> select * from v$asm_operation ;

GROUP_NUMBER OPERA STAT POWER ACTUAL SOFAR EST_WORK
------------ ----- ---- ----- ------ ----- --------
EST_RATE EST_MINUTES
-------- -----------
1 REBAL RUN 1 1 3020 3226
1972 0


SQL> select * from v$asm_operation ;

no rows selected

SQL> ALTER DISKGROUP P1CSM2_ASM_DG1 DROP DISK P1CSM2_ASM_DG1_0002 ;

Diskgroup altered.

SQL> select * from v$asm_operation ;

GROUP_NUMBER OPERA STAT POWER ACTUAL SOFAR EST_WORK
------------ ----- ---- ----- ------ ----- --------
EST_RATE EST_MINUTES
-------- -----------
1 REBAL RUN 1 1 1513 3197
1957 0

SQL> select * from v$asm_operation ; no rows selected SQL>



7. Check the removal of the disk volumes.
SQL> select disk_number, mode_status, name, path from v$asm_disk where group_number = 1 order by disk_number, name ;

DISK_NUMBER MODE_ST NAME
----------- ------- ------------------------------
PATH
------------------------------------------------------------------
3 ONLINE P1CSM2_ASM_DG1_0010
/dev/rrawlv01
4 ONLINE P1CSM2_ASM_DG1_0011
/dev/rrawlv02
5 ONLINE P1CSM2_ASM_DG1_0012
/dev/rrawlv03

SQL>