You can connect as SYSDBA to use SQL*Plus or ASMCMD commands to manage Oracle ASM components associated with the database. When running SQL or ASMCMD operations with the SYSDBA privilege, connect to the database instance rather than the Oracle ASM instance.
Connecting as SYSDBA to the database instance has a limited set of Oracle ASM privileges. For example, you cannot create a disk group when connected with the SYSDBA privilege.
When connected as SYSDBA to the database instance, the Oracle ASM operations are limited to:
Create and delete files, aliases, directories, and templates
Examine various Oracle ASM instance views
Operate on files that were created by this user or only access files to which another user had explicitly granted access
Granting Oracle ASM File Access Control to other users