Table of contents
Collapse the table of content
Expand the table of content

Deploy NVMe Storage Devices using Discrete Device Assignment

Chris Huybregts|Last Updated: 2/15/2017
1 Contributor

Applies To: Microsoft Hyper-V Server 2016, Windows Server 2016

Starting with Windows Server 2016, you can use Discrete Device Assignment, or DDA, to pass an entire PCIe Device into a VM. This will allow high performance access to devices like NVMe storage or Graphics Cards from within a VM while being able to leverage the devices native drivers. Please visit the Plan for Deploying Devices using Discrete Device Assignment for more details on which devices work, what are the possible security implications, etc. There are three steps to using a device with DDA:

  • Configure the VM for DDA
  • Dismount the Device from the Host Partition
  • Assigning the Device to the Guest VM

All command can be executed on the Host on a Windows PowerShell console as an Administrator.

Configure the VM for DDA

Discrete Device Assignment imposes some restrictions to the VMs and the following step needs to be taken.

  1. Configure the “Automatic Stop Action” of a VM to TurnOff by executing
Set-VM -Name VMName -AutomaticStopAction TurnOff

Dismount the Device from the Host Partition

Locating the Device’s Location Path

The PCI Location path is required to dismount and mount the device from the Host. An example location path looks like the following: "PCIROOT(20)#PCI(0300)#PCI(0000)#PCI(0800)#PCI(0000)". More details on located the Location Path can be found here: Plan for Deploying Devices using Discrete Device Assignment.

Disable the Device

Using Device Manager or PowerShell, ensure the device is “disabled.”

Dismount the Device

Dismount-VMHostAssignableDevice -LocationPath $locationPath

Assigning the Device to the Guest VM

The final step is to tell Hyper-V that a VM should have access to the device. In addition to the location path found above, you'll need to know the name of the vm.

Add-VMAssignableDevice -LocationPath $locationPath -VMName VMName

What’s Next

After a device is successfully mounted in a VM, you’re now able to start that VM and interact with the device as you normally would if you were running on a bare metal system. You can verify this by opening device manager in the Guest VM and seeing that the hardware now shows up.

Removing a Device and Returning it to the Host

If you want to return he device back to its original state, you will need to stop the VM and issue the following:

#Remove the device from the VM
Remove-VMAssignableDevice -LocationPath $locationPath -VMName VMName
#Mount the device back in the host
Mount-VMHostAssignableDevice -LocationPath $locationPath

You can then re-enable the device in device manager and the host operating system will be able to interact with the device again.

© 2017 Microsoft