oracle 11gr2 asm instance shutdown

[oracle@asm1 gan]$ su - grid
Password:
[grid@asm1 ~]$ ls -l
total 4
drwxr-xr-x  3 grid oinstall 4096 Jun 20 14:19 oradiag_grid
[grid@asm1 ~]$ env |grep ORACLE
ORACLE_SID=+ASM
ORACLE_BASE=/u01/app
ORACLE_HOME=/u01/app/grid
[grid@asm1 ~]$ sqlplus "/as sysasm"

SQL*Plus: Release 11.2.0.1.0 Production on Wed Nov 2 14:44:28 2011

Copyright (c) 1982, 2009, Oracle.  All rights reserved.


Connected to:
Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - Production
With the Automatic Storage Management option

SQL> shutdown immediate;
ASM diskgroups dismounted
ASM instance shutdown
SQL> startup;
ASM instance started

Total System Global Area  284565504 bytes
Fixed Size                  1336036 bytes
Variable Size             258063644 bytes
ASM Cache                  25165824 bytes
ASM diskgroups mounted
SQL> exit
Disconnected from Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - Production
With the Automatic Storage Management option
[grid@asm1 ~]$ exit
logout

[oracle@asm1 gan]$ env |grep ORACLE
ORACLE_SID=+ASM
ORACLE_BASE=/u02/app
ORACLE_HOME=/u01/app/grid
[oracle@asm1 gan]$ sqlplus "/as sysasm"

SQL*Plus: Release 11.2.0.1.0 Production on Wed Nov 2 14:45:16 2011

Copyright (c) 1982, 2009, Oracle.  All rights reserved.

ERROR:
ORA-01031: insufficient privileges


Enter user-name:


11g R2的Oracle ASM Instance有变化了。以前直接sqlplus "/as sysdba" shutdown不可以用了。
需要切换到grid用户后sqlplus "/as sysasm"才可以。