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7.2.2. Configuration changes for Windows virtual machines


Before converting Windows virtual machines, ensure that the libguestfs-winsupport and virtio-win packages are installed on the host running virt-v2v. These packages provide support for NTFS and Windows paravirtualized block and network drivers. If you attempt to convert a virtual machine using NTFS without the libguestfs-winsupport package installed, the conversion will fail. If you attempt to convert a virtual machine running Windows without the virtio-win package installed, the conversion will fail giving an error message concerning missing files. See Section, “Preparing to convert a virtual machine running Windows” for details.
virt-v2v can convert virtual machines running Windows XP, Windows Vista, Windows 7, Windows Server 2003 and Windows Server 2008. The conversion process for virtual machines running Windows is slightly to different to the process for virtual machines running Linux. Windows virtual machine images are converted as follows:
  1. virt-v2v installs VirtIO block drivers.
  2. virt-v2v installs the CDUpgrader utility.
  3. virt-v2v copies VirtIO block and network drivers to %SystemRoot%\Drivers\VirtIO. The virtio-win package does not include network drivers for Windows 7 and Windows XP. For those operating systems, the rtl8139 network drivers are used. rtl8139 support must be already available in the guest virtual machine.
  4. virt-v2v adds %SystemRoot%\Drivers\VirtIO to DevicePath, meaning this directory is automatically searched for drivers when a new device is detected.
  5. virt-v2v makes registry changes to include the VirtIO block drivers in the CriticalDeviceDatabase section of the registry, and ensure the CDUpgrader service is started at the next boot.
At this point, virt-v2v has completed the conversion. The converted virtual machine is now fully functional, and the conversion is complete for output to KVM managed by libvirt. If the virtual machine is being converted for output to Red Hat Enterprise Virtualization, the Red Hat Enterprise Virtualization Manager will perform additional steps to complete the conversion:
  1. The virtual machine is imported and run on the Manager. See the Red Hat Enterprise Virtualization Administration Guide for details.


    The first boot stage can take several minutes to run, and must not be interrupted. It will run automatically without any administrator intervention other than starting the virtual machine. To ensure the process is not interrupted, no user should log in to the virtual machine until it has quiesced. You can check for this in the Manager GUI.
  2. If the guest tools ISO has been uploaded to the Manager, as detailed in Section, “Preparing to convert a virtual machine running Windows”, the Manager attaches the guest tools CD to the virtual machine.
  3. CDUpgrader detects the guest tools ISO and installs all the VirtIO drivers from it, including additional tools that are not included in virtio-win. The VirtIO drivers are reinstalled if the drivers in the guest tools ISO are newer than the ones previously installed from virtio-win. This ensures that the tools are kept up to date.