SYSASM role was introduced in 11gR1 and was designed to administer ASM instances. In 11gR1 , if you connected with SYSDBA role , you used to get a warning which was only recorded in alert log (Refer to my earlier post here). But things have changed in 11gR2. While trying to dismount a Diskgroup, I found following errors
SQL> alter diskgroup flash_arc mount; alter diskgroup flash_arc mount * ERROR at line 1: ORA-15032: not all alterations performed ORA-15260: permission denied on ASM disk group
Above error indicates that I do not have permission on the ASM Diskgroup. As per 11gR2 documentation, SYSASM privilege is used for carrying out administration tasks on ASM Diskgroups. SYSDBA privilege can be used only for creating/deleting aliases and querying ASM dictionary views. Frankly speaking, you should unlearn the habit of connecting as "/ as sysdba" to ASM instance and learn connecting as "/ as sysasm"