Quote from Microsoft FAQ for Storage Spaces:
What types of drives can I use with Storage Spaces?
You can use commodity drives attached via Serial-Attached SCSI (SAS), Serial ATA (SATA), or USB. Storage layers that abstract the physical disks are not compatible with Storage Spaces. This includes VHDs and pass-through disks in a virtual machine, and storage subsystems that layer a RAID implementation on top of the physical disks. iSCSI and Fibre Channel controllers are not supported by Storage Spaces.