如何删除asm Diskgroup

[oracle@racdb1 ~]$ export ORACLE_SID=+ASM1
[oracle@racdb1 ~]$ sqlplus "/as sysdba"

SQL*Plus: Release 10.2.0.4.0 - Production on Wed Feb 8 14:08:05 2012

Copyright (c) 1982, 2007, Oracle.  All Rights Reserved.

Connected to:
Oracle Database 10g Enterprise Edition Release 10.2.0.4.0 - 64bit Production
With the Partitioning, Real Application Clusters, OLAP, Data Mining
and Real Application Testing options

 

SQL> select name,state from v$asm_diskgroup;

NAME                           STATE
------------------------------ -----------
DATA                           MOUNTED
FRA                            DISMOUNTED
ARCH                           MOUNTED

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

SQL> alter diskgroup FRA mount;

Diskgroup altered.

SQL> drop diskgroup FRA;

Diskgroup dropped.

SQL> select name,state from v$asm_diskgroup;

NAME                           STATE
------------------------------ -----------
DATA                           MOUNTED
ARCH                           MOUNTED