So, SYSDBA does not have privileges to administer ASM instance any more!!! OK fine we will start using SYSASM role to administer then...
/home/oracle:(+ASM)$ sqlplus /nolog
SQL*Plus: Release 11.2.0.1.0 Production on Fri Oct 8 13:50:43 2010
Copyright (c) 1982, 2009, Oracle. All rights reserved.
SQL> conn / as sysdba
Connected.
SQL> shutdown
ORA-01031: insufficient privileges
Now try this:
SQL> conn / as sysasm
Connected.
SQL> shutdown
SQL> database dismounted.
As I said something to learn new everyday... things are never same...