Use Virtualization in Windows Server 2012 - MCSA Windows Server 2012 R2: Installation and Configuration Study Guide - page 457

You cannot share a physical disk among multiple virtual machines or with
the host system.

Physical or pass-through disks might not be that important if your use of virtualization
is based on test environments, but they become crucial when you need to plan for highly
available virtual datacenters. This is especially true if you consider using failover clusters
to provide the Quick Migration feature, which is when you should consider matching one
logical unit number (LUN) from your enterprise storage system or storage area network
(SAN) as one physical disk. This provides you with the optimum performance you need in
such an environment.

Managing Virtual Hard Disks
Hyper-V also provides two tools to manage virtual hard disks: Inspect Disk and Edit Disk.
These tools are available on the Actions pane in Hyper-V Manager.
Inspect Disk This provides you with information about the virtual hard disk. It shows you
not only the type of the disk but also information such as the maximum size for dynami-
cally expanding disks and the parent VHD for differencing disks.
Edit Disk This provides you with the Edit Virtual Hard Disk Wizard, which you can use
to compact, convert, expand, merge, or reconnect hard disks. Figure 9.9 shows you the wiz-
ard's options when you select a dynamically expanding disk.

figUre 9.9 The Edit Virtual Hard Disk Wizard