The Policy.DiskPolicySpec structure provides a specification for the storage policy to be associated with the virtual disks.
Storage Policy identification. This field is optional and it is only relevant when the value of Policy.DiskPolicySpec.type is USE_SPECIFIED_POLICY. When clients pass a value of this structure as a parameter, the field must be an identifier for the resource type: com.vmware.vcenter.StoragePolicy. When operations return a value of this structure as a result, the field will be an identifier for the resource type: com.vmware.vcenter.StoragePolicy.
Policy type to be used while performing update operation on the virtual disks.