Tip: Convert a Physical Disk to a VHD (Virtual Hard Disk)

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Hyper-V allows you to duplicate the contents of a physical drive into a new virtual hard disk. There are several requirements to consider when using this method to migrate the contents of the physical disk into a virtual hard disk.

The limitations are as follows:

  • VHD copy is limited to converting a physical disk, not a volume or a partition.
  • VHD copy must be used only to migrate a data disk; operating system disk migration is not supported.
  • VHD copy should be used to convert a physical disk that is not being accessed by the host operating system or applications during the conversion process.
  • VHD copy requires that if the physical disk that is being converted is larger than 127 gigabytes (GB), you must attach the virtual hard disk into which the disk contents will be copied to a virtual SCSI adapter.

Depending on the size of the physical disk that you select to copy to a VHD, this process can take a considerable amount of time.

Note that prior to starting the VHD copy, you should use the Disk Management Microsoft Management Console (MMC) or other similar tool to remove the drive letter for the target drive. This will make the drive inaccessible to the host operating system, preventing disk corruption during the conversion process.

The process to create a new virtual hard disk from a physical disk is simple. To begin the process and copy the physical drive content to a new virtual hard disk, follow these steps:
1. Open the Hyper-V Manager console.
2. In the Actions pane, under the server name, click New and then select Hard Disk from the menu to launch the New Virtual Hard Disk Wizard.
3. On the Before You Begin page, click Next.
4. On the Choose Disk Type page, select the type of disk to create (Dynamically Expanding or Fixed Size) and then click Next.
5. On the Specify Name And Location page, type a name for the new virtual hard disk in the Name text box and then type a fully qualified path to the storage folder in the Location text box, or click Browse to use Windows Explorer to select the storage folder. After you complete these actions, click Next.
6. On the Configure Disk page, select Copy The Contents Of The Specified Physical Disk and then click the physical hard disk that you want to convert from the list that is presented. After you complete these actions, click Next.
7. On the Completing The New Virtual Hard Disk Wizard page, review your selections.
8. Click Finish.

Note that you should use a fixed-size disk as the target for the VHD conversion unless you have a requirement for dynamic expansion of the virtual hard disk.

From the Microsoft Press book Windows Server 2008 Hyper-V Resource Kit by Robert Larson and Janique Carbone with the Windows Virtualization Team at Microsoft.

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