[root@node1:/root/]#su - grid
[grid@node1 ~]$ sqlplus / as sysdba
SQL*Plus: Release 11.2.0.1.0 Production on Sun Nov 29 21:04:37 2015
Copyright (c) 1982, 2009, Oracle.  All rights reserved.
Connected to:
Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - Production
With the Real Application Clusters and Automatic Storage Management options

SQL> ALTER DISKGROUP dg1 CHECK ALL;
ALTER DISKGROUP dg1 CHECK ALL
*
ERROR at line 1:
ORA-15032: not all alterations performed
ORA-15260: permission denied on ASM disk group

SQL> 
SQL> conn / as sysasm 
Connected.
SQL> ALTER DISKGROUP dg1 CHECK ALL;


Diskgroup altered.


SQL>