Difference between pages "VMWare Virtual Disk Format (VMDK)" and "Virtual Hard Disk (VHD)"

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The Virtual Hard Disk (VHD) commonly uses the .vhd extension.
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This format is used to store virtual disk images by:
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* Microsoft Virtual PC
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* Microsoft Virtual Server
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* Microsoft Hyper-V Server
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VHD support is also integrated into [[Windows]] (at least in Windows 7) where "Disk Management" (part of "Computer Management") supports attaching and creating Fixed and Dynamic VHD image files.
  
 
== Image types ==
 
== Image types ==
There are multiple types of VMWare Virtual Disk Format (VMDK) files:
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There are multiple types of Virtual Hard Disk (VHD) images:
* '''2GbMaxExtentFlat''' (or '''twoGbMaxExtentFlat'''); descriptor file (name.vmdk) with RAW extent data files (name-f###.vmdk). This image type is basically a [[Raw Image Format|split RAW image]].
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* Fixed-size hard disk image; the image contains all data
* '''2GbMaxExtentSparse''' (or '''twoGbMaxExtentSparse'''); descriptor file (name.vmdk) with VMDK sparse extent data files (name-s###.vmdk)
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* Dynamic-size (or sparse) hard disk image; the image contains used data only
* '''monolithicFlat'''; descriptor file (name.vmdk) with RAW extent data file (name-f001.vmdk). This image type is basically a [[Raw Image Format|RAW image]].
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* Differential (or differencing, or delta) hard disk image; the image contains changes relative to its parent image
* '''monolithicSparse'''; VMDK sparse extent data file (name.vmdk) which contains the descriptor file data.
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== Descriptor file ==
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== Snapshots ==
The descriptor file defines how and where the data of the VMDK image is stored. The data is stored in extent data files.
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Hyper-V has functionality to create snapshots.  
  
== Extent data file types ==
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These snapshots are stored in Snapshot Differencing Disk (AVHD) files which commonly uses the .avhd extension.
There are multiple types extent data files:
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* RAW extent data file or device
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* VMDK sparse extent data file
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* COWD sparse extent data file
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Note that the '''VMDK sparse extent data file''' can be in a '''dirty state''' (or uncleanShutdown).
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The snapshot can be interdependent on one-another, because they are differential images of the previous snapshot.
  
 
== See Also ==
 
== See Also ==
 
* [[Disk Images]]
 
* [[Disk Images]]
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* [[Windows]]
  
 
== External Links ==
 
== External Links ==
* [http://www.vmware.com/support/developer/vddk/vmdk_50_technote.pdf?src=vmdk Virtual Disk Format 5.0], by [[VMWare]]
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* [https://googledrive.com/host/0B3fBvzttpiiSQ1dOUmhqMkR2cm8/VMWare%20Virtual%20Disk%20Format%20(VMDK).pdf VMware Virtual Disk (VMDK) format specification], by the [[libvmdk|libvmdk project]]
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* [http://en.wikipedia.org/wiki/VHD_(file_format) VHD (file format)], by Wikipedia
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* [http://technet.microsoft.com/en-us/library/bb676673.aspx Virtual Hard Disk Image Format Specification], by Microsoft, October 2006
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* [https://googledrive.com/host/0B3fBvzttpiiSY250RjRzRXQ0bDg/Virtual%20Hard%20Disk%20(VHD)%20image%20format.pdf Virtual Hard Disk (VHD) image format], by the [[libvhdi|libvhdi project]], September 2012
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=== Snapshots ===
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* [http://social.technet.microsoft.com/wiki/contents/articles/670.hyper-v-concepts-snapshots.aspx Hyper-V Concepts - Snapshots]
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* [http://blogs.msdn.com/b/virtual_pc_guy/archive/2008/03/11/virtual-machine-snapshotting-under-hyper-v.aspx Virtual Machine Snapshotting under Hyper-V]
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* [http://www.msserveradmin.com/hyper-v-snapshot-files-avhd-and-vhd-what-the/ Hyper-V SnapShot Files – AVHD and VHD? What The ?]
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* [http://social.technet.microsoft.com/wiki/contents/articles/6257.manually-merge-avhd-to-vhd-in-hyper-v.aspx Manually Merge .avhd to .vhd in Hyper-V]
  
 
[[Category:File Formats]]
 
[[Category:File Formats]]

Revision as of 01:26, 15 July 2013

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Please help to improve this article by expanding it.
Further information might be found on the discussion page.

The Virtual Hard Disk (VHD) commonly uses the .vhd extension.

This format is used to store virtual disk images by:

  • Microsoft Virtual PC
  • Microsoft Virtual Server
  • Microsoft Hyper-V Server

VHD support is also integrated into Windows (at least in Windows 7) where "Disk Management" (part of "Computer Management") supports attaching and creating Fixed and Dynamic VHD image files.

Image types

There are multiple types of Virtual Hard Disk (VHD) images:

  • Fixed-size hard disk image; the image contains all data
  • Dynamic-size (or sparse) hard disk image; the image contains used data only
  • Differential (or differencing, or delta) hard disk image; the image contains changes relative to its parent image

Snapshots

Hyper-V has functionality to create snapshots.

These snapshots are stored in Snapshot Differencing Disk (AVHD) files which commonly uses the .avhd extension.

The snapshot can be interdependent on one-another, because they are differential images of the previous snapshot.

See Also

External Links

Snapshots