You cannot create a CDS disk group when encapsulating an existing disk, or when converting an LVM volume.
When initializing a disk, if the target disk group is an existing CDS disk group, vxdiskadm will only allow the disk to be initialized as a CDS disk. If the target disk group is a non-CDS disk group, the disk can be initialized as either a CDS disk or a non-CDS disk.
If you use the vxdiskadm command to initialize a disk into an existing CDS disk group, the disk must have be added with the cdsdisk format.
The CDS attribute for the disk group remains unchanged by this procedure.