Skip to main content

Convert a physical install to VM

This guide aims to explain the steps required to convert a physical Linux or Windows computer to a VM, and use it in Unraid.

Steps 1-3 apply for almost any modern Linux-based guest. Steps 4-6 apply for Windows-based guests.


  • Your system must meet the hardware requirements and complete these preparation steps before utilizing virtual machines on Unraid Server OS 6.
  • You must have enough disk space available on a single storage device in your array (total free space in the cache pool) that is equal to or greater in size than the physical disk you wish to convert.
  • It is highly encouraged to make a complete backup of your most important files before attempting a conversion.

Step 1: Identify the disk to be converted using the Unraid WebGUI

  • With the array stopped, attach the physical disk you wish to convert to your server (SATA and power)
  • Login to your Unraid WebGUI (http://tower or http://tower.local)
  • Click the Main tab.
  • If the array hasn't been started yet, start it by clicking Start.
  • Locate your disk device from the Unassigned Devices section on the Main tab.
  • Under the identification column, notate the disk id by letter handle (e.g. sdb, sdc, sdd, sde, ...)
  • Also make note of the size, as you will need at least this much space free on an available array device or the cache (pool) to create your new virtual disk.

Step 2: Add a new Virtual Machine from the VMs tab

  • Login to your Unraid WebGUI (http://tower or http://tower.local)
  • Click on the VMs tab (if the tab isn't visible, you haven't completed these preparation steps or may not meet the hardware requirements; post in general support for further assistance)
  • Click the Add VM button.
  • Follow this guide to create your VM, making sure to adhere to these specific settings:
    • Leave the BIOS setting to SeaBIOS.
    • Leave OS Install ISO blank.
    • Be sure to have the VirtIO Drivers ISO specified, you will need these in a later step.
    • Make the primary virtual disk large enough for the physical disk you are copying.
    • If converting a disk containing a Windows OS
      • Add a second virtual disk by clicking the green plus symbol
      • Make the size of this second virtual disk 1M.
      • Uncheck the option to Start VM after creation

Step 3: Convert disk to image

  • Utilizing a telnet or SSH capable client, connect to your Unraid system over a Local Area Network. The default username is root and there is no password by default.
  • Enter the following command to begin the conversion of your physical disk to a virtual image:
qemu-img convert -p -O raw /dev/sdX /mnt/user/vdisk_share/vmname/vdisk1.img
  • Replace sdX with the device letter handle you noted in step 1, replace vdisk_share with the share you created to store your virtual disks, and replace vmname with the name you gave it when you created it in step 2.
  • The -p tag will output progress in the form of a percentage while the conversion is occurring.

Step 4: Edit the XML for your virtual machine (Windows Guests Only)

  • From the VMs tab, click the VM icon and select Edit XML from the context menu.
  • Scroll down the XML and locate the <target> tag for the <disk> with a <source> file set to vdisk1.img, which will look like such:
<disk type='file' device='disk'>
<driver name='qemu' type='raw' cache='writeback'/>
<source file='/mnt/cache/vdisk_share/vmname/vdisk1.img'/>
<target dev='hda' bus='virtio'/>
<boot order='1'/>
<alias name='virtio-disk0'/>
<address type='pci' domain='0x0000' bus='0x00' slot='0x05' function='0x0'/>
  • Adjust vdisk1.img by changing the bus attribute to the <target> tag to ide.
  • Delete the entire <address> line for that <disk>.
  • Corrected XML example below:
<disk type='file' device='disk'>
<driver name='qemu' type='raw' cache='writeback'/>
<source file='/mnt/cache/vdisk_share/vmname/vdisk1.img'/>
<target dev='hda' bus='ide'/>
<boot order='1'/>
  • Click Update to update the virtual machine XML.

Step 5: Install the VirtIO drivers from inside the VM (Windows Guests Only)

  • Using Windows File Explorer, navigate to the VirtIO virtual CD-ROM to browse its contents.
    • Navigate inside the Balloon folder.
    • Navigate to the subfolder named after your Windows OS version (e.g. w8.1)
    • Navigate to the amd64 subfolder
    • Right-click on the balloon.inf file inside and click Install from the context menu (you may need to enable viewing of file extensions to do this)
  • Repeat the above process for each of the following folders:
    • NetKVM
    • vioserial
    • viostor
  • When done installing drivers, navigate inside the virtual cd-rom one more time and open the guest-agent folder.
  • Double-click on qemu-ga-x64.msi to install the QEMU/KVM guest agent.

Step 6: Remove the secondary vdisk from your VM (Windows Guests Only)

  • Shutdown your VM if it isn't already.
  • From the VMs tab, click the VM icon and select Edit from the context menu.
  • Remove the vdisk2.img virtual disk by clicking the red minus symbol.
  • Click Update to update the VM.
  • Start your newly converted virtual machine!

If you are stuck at SeaBIOS with "Booting from Hard Disk"

If your OS was installed using UEFI (as opposed to traditional VGA BIOS), start over from step 3, but select OVMF as the BIOS type instead of SeaBIOS. Most OS installations install using a traditional VGA BIOS, but it is possible to have a UEFI installation, in which case SeaBIOS will not work. The remainder of the conversion procedure is identical.