Dell EMC PowerVault MD 34XX/38XX Series Storage Arrays Administrator's Guide

You can create disk groups and virtual disks in the storage array. You must select the capacity that you want to allocate for the virtual disk from either unconfigured capacity, free capacity, or an existing disk pool available in the storage array. Then you define basic and optional advanced parameters for the virtual disk.

With the advent of different physical disk technologies, it is now possible to mix physical disks with different media types and different interface types within a single storage array.