Deleting a dynamic disk group can be done two ways.
The recommended procedure is a two-part process and is described as follows:
First, all the volumes in the dynamic disk group must be moved or deleted by using the Delete Volume command, then all the disks in the dynamic disk group must be removed from the disk group by using the Remove Disk from Dynamic Disk Group command. Once you remove all the disks from a dynamic disk group, the dynamic disk group is automatically deleted.
The alternative procedure is to use the Destroy Dynamic Disk Group command, which permanently removes the disk group and all its volumes in a one-step process.