Enter the following command:vol create volname -n -m ndisks[@disk-size]
volname is the name of the mirrored volume you are creating (without the /vol/ prefix).
-n instructs Data ONTAP not to create the mirrored volume, but to display the disks that it would use if it did create the mirrored volume.
-m specifies a mirrored volume to Data ONTAP.
ndisks is the number of disks to use. ndisks must be an even number.
disk-size specifies the disk capacity, in gigabytes. You must have enough available disks of the size you specify.
Example
Data ONTAP returns a vol create command that specifies the disks.