The initialization parameters for ASM instance

The initialization parameters that are of specific interest for an ASM instance are:
•INSTANCE_TYPE - Set to ASM or RDBMS depending on the instance type. The default is RDBMS.
•DB_UNIQUE_NAME - Specifies a globally unique name for the database. This defaults to +ASM but must be altered if you intend to run multiple ASM instances.
•ASM_POWER_LIMIT -The maximum power for a rebalancing operation on an ASM instance. The valid values range from 1 to 11, with 1 being the default. The higher the limit the more resources are allocated resulting in faster rebalancing operations. This value is also used as the default when the POWER clause is omitted from a rebalance operation.
•ASM_DISKGROUPS - The list of disk groups that should be mounted by an ASM instance during instance startup, or by the ALTER DISKGROUP ALL MOUNT statement. ASM configuration changes are automatically reflected in this parameter.
•ASM_DISKSTRING - Specifies a value that can be used to limit the disks considered for discovery. Altering the default value may improve the speed of disk group mount time and the speed of adding a disk to a disk group. Changing the parameter to a value which prevents the discovery of already mounted disks results in an error. The default value is NULL allowing all suitable disks to be considered.
Incorrect usage of parameters in ASM or RDBMS instances result in ORA-15021 errors.