How to drop a dismounted ASM disk group?

Problem :

I was not able to Mount or Drop ASM disk group.

SQL> select group_number, name, STATE from v$asm_diskgroup;

GROUP_NUMBER NAME STATE
------------ ------------------------------ -----------
3 RAC_DATA1 DISMOUNTED
4 RAC_DATA2 DISMOUNTED
3 RAC_DG1 MOUNTED
4 RAC_DG2 MOUNTED

SQL> drop diskgroup RAC_DATA1;
drop diskgroup RAC_DATA1
*
ERROR at line 1:
ORA-15039: diskgroup not dropped
ORA-15001: diskgroup "RAC_DATA1" does not exist or is not mounted

SQL> alter diskgroup RAC_DATA1 mount;
alter diskgroup RAC_DATA1 mount
*
ERROR at line 1:
ORA-15032: not all alterations performed
ORA-15024: discovered duplicately numbered ASM disk 0

Solution


I have followed ML Note:268481.1
Re-creating ASM Instances and Diskgroups

I have used force option while creating diskgroups