ASM_DISKGROUPS

The ASM_DISKGROUPS initialization parameter specifies a list of disk group names that an Oracle ASM instance mounts at startup when the SQL ALTER DISKGROUP ALL MOUNT statement is issued. The Oracle ASM instance startup process executes ALTER DISKGROUP ALL MOUNT unless the NOMOUNT startup option is specified.

The default value of the ASM_DISKGROUPS parameter is a NULL string. For information about disk groups that are mounted at startup time, see "About Mounting Disk Groups at Startup".

The ASM_DISKGROUPS parameter is dynamic. If you are using a server parameter file (SPFILE), then you do not have to manually alter the value of ASM_DISKGROUPS. Oracle ASM automatically adds a disk group to the parameter when the disk group is successfully created or mounted. Oracle ASM also automatically removes a disk group from the parameter when the disk group is dropped or dismounted.

The following is an example of setting the ASM_DISKGROUPS parameter dynamically:

SQL> ALTER SYSTEM SET ASM_DISKGROUPS = DATA, FRA;

When using a text initialization parameter file (PFILE), you may edit the initialization parameter file to add the name of any disk group so that it is mounted automatically at instance startup. You must remove the name of any disk group that you no longer want automatically mounted.

The following is an example of the ASM_DISKGROUPS parameter in the initialization file:

ASM_DISKGROUPS = DATA, FRA

For additional information about mounting Oracle ASM disk groups, see "Mounting and Dismounting Disk Groups".

For Oracle Database 12c Release 1 or later, Oracle ASM configurations support up to 511 disk groups. Oracle ASM configurations with Oracle Database releases before 12c Release 1 can only support up to 63 disk groups.