ASM Disk Addition & Deletion
2 min readAdding Disks to a Disk Group is done with the “alter diskgroup” command.
Oracle provides the alter diskgroup command to adding or removing physical disks within SQL*Plus:
First we identify the ASM diskgroup where we want to add the disk:
Login as: sys as sysasm
SQL> select group_number,name from v$asm_diskgroup;
GROUP_NUMBER NAME
------------ ------------------------------
1 DATA_FILES
2 DATA_FRA
3 DATA
Next, we identify the disks to see which disk should be added to the diskgroup:
set lin 200 pages 200
col path for a20
select mount_status,header_status,mode_status,state,total_mb,free_mb,name,path,label from v$asm_disk;
MOUNT_S HEADER_STATU MODE_ST STATE TOTAL_MB FREE_MB NAME PATH LABEL
------- ------------ ------- -------- ---------- ---------- ------------------------------ -------------------- -------------------------------
CACHED MEMBER ONLINE NORMAL 1024 715 DATA_0002 /dev/mapper/sdd
CACHED MEMBER ONLINE NORMAL 51200 8046 DATA_FILES_0000 /dev/mapper/sde
CACHED MEMBER ONLINE NORMAL 1024 714 DATA_0000 /dev/mapper/sdb
CACHED MEMBER ONLINE NORMAL 1024 714 DATA_0001 /dev/mapper/sdc
CACHED MEMBER ONLINE NORMAL 51200 50510 DATA_FRA_0000 /dev/mapper/sdg
IF HDD IS NOT VISIBLE THEN WE CAN SET THE PARAMETER
SQL> Alter system set asm_diskstring='/dev/sd*' ;
Now, we can add the disk to the ASM diskgroup:
SQL> Alter diskgroup DATA add disk '/dev/sdg';
SQL> Alter diskgroup DATA add disk '/dev/sdh';
CHECK THE TIME TAKEN TO REBALANCING
SQL> select operation,state,EST_MINUTES from v$asm_operation;
SQL> select * from v$asm_operation;
We can delete the disk from the ASM diskgroup:
SQL> Alter diskgroup DATA drop disk DATA_0000
SQL> Alter diskgroup DATA drop disk DATA_FILES_0001
INCREASE POWER LIMIT OF ASM REBALANCING
SQL> show parameter limit
NAME TYPE VALUE
------------------- ----------- ------
asm_power_limit integer 1
SQL> Alter diskgroup DATA rebalance power 2;
Refer for more ASM related commands: https://asrblogger.com/asm-scripts/
