Virtualization Technology News and Information
New Sizing Utility Pops up for Microsoft's VHD Format

Personally, I've been complaining about this "missing feature" from Microsoft's virtualization platform for quite some time.  What feature?  A VHD resizer tool.  Seems simple, right?  Then why didn't Microsoft have this in the product? 

What am I talking about?  In today's world of virtual machine cloning, what happens if you create a virtual machine with one size, and then realize that either the clones or the base image itself needs to have more space.  What do you do?  I suppose you can try to image it or migrate it over to another virtual hard disk with a larger max size, but why?  Why, when you have a perfectly good image (except for being too small that is) already!

VMware has this feature in its product and control repertoire.  So, it must have been deemed useful to someone along the way.

Enter Xtralogic's VHD Utility.

Microsoft Virtual PC and Microsoft Virtual server do not have a functionality to increase a storage capacity of a Virtual Hard Disk (VHD). At the same time it is quite easy to underestimated storage requirements of a virtual machine. This problem may be especially annoying for fixed VHDs, used due to improvement in performance they offer, since it is not desirable to allocate too much storage space for them from the beginning. The standard solution for this problem used to be using Ghost inside of the guest OS to create an image, and restoring the image to a bigger, newly created VHD, attached to the same virtual machine. This procedure sure works, but it is painfully slow and laborious manual process.

VHD Utility offers a better solution. It can expand VHD, based on its knowledge of the VHD format, in one operation and has a convenient intuitive GUI (context menu on a VHD file). Just right click a VHD file in Windows Explorer and follow a simple wizard. The extension operation is going to be almost simultaneous if you choose to expand a VHD in place (make sure you have a current backup), or it will take some time, needed to copy the data, if you choose to leave the original VHD intact and expand a copy of the original VHD. After a VHD is expanded using VHD utility one additional step will be required inside of the guest OS to extend a file system partition.



  • Expands dynamic and fixed VHDs
  • Displays VHD information(VHD storage capacity, allocated size, VHD type)
  • Intuitive and easy to use GUI integrated into Windows Explorer context menu for a VHD file
  • Command line interface


The only downside, it isn't free.  It looks like a single user license will run you $19.95.  The product is offering a free 30 day evaluation and can be downloaded here.  Check it out more by visiting the Web site.

Xtralogic is charging money for this utility, and while it does what I need, I have to wonder how long before Microsoft or someone else recreates this functionality for free what with the VHD spec being opened up to people.

Thanks to Richard Cardona for sending this our way!

Published Sunday, October 29, 2006 5:36 PM by David Marshall
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