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 . 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 AS
Can ASM DiskGroup Be Renamed?
Answer is NO. It is not possible to rename the diskgroup by editing the ASM disk header. kfed is known to be used for patching ASM disk headers for corruption (only oracle support can do it) and for viewing ASM header contents. Only way to change this by dropping and recreating the diskgroup.
In case you wish to create a new diskgroup with a name say +DG1 which was being used by a Diskgroup which is not mounted (Have some ASM Disk members still in ASM_DISKSTRING path), then you would face following error
<strong>ORA-15030</strong>: diskgroup name "string" is in use by another diskgroup <strong>Cause:</strong> A CREATE DISKGROUP command specified a Diskgroup name that was already assigned to another diskgroup. <strong>Action: </strong>Select a different name for the Diskgroup.
In case you wish to create the Diskgroup with same name +DG1 you will be required to clear the ASM disk header using
dd if=/dev/zero of=/dev/raw/raw11 bs=1024 count=100
After this you can recreate the Diskgroup with same name.
M instance and learn connecting as “/ as sysasm”