ORA-15032: not all alterations performed ORA-15260: permission denied on ASM disk group

When you add disks to ASM if you will get the following error :

SQL> ALTER DISKGROUP DATADG ADD DISK 'ORCL:DATADG2' REBALANCE POWER 11;
ALTER DISKGROUP DATADG ADD DISK 'ORCL:DATADG2' REBALANCE POWER 11
*
ERROR at line 1:
ORA-15032: not all alterations performed
ORA-15260: permission denied on ASM disk group

Solution : 

Connect as sysasm and try to run the commands.

[grid@node4 ~]$ sqlplus / as sysasm

SQL*Plus: Release 11.2.0.4.0 Production on Mon Jun 10 17:12:36 2019

Copyright (c) 1982, 2013, Oracle.  All rights reserved.

Connected to:

Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production

With the Real Application Clusters and Automatic Storage Management options

SQL> select * from v$asm_operation;                                    

no rows selected

SQL> ALTER DISKGROUP DATADG ADD DISK 'ORCL:DATADG2' REBALANCE POWER 11;

Diskgroup altered.