Since I posted on being able to boot from a VHD, I have heard the same question time and time again. That’s (somewhat) cool, but why would I ever want to do that? Especially when compared to either booting from a partition or hosting within a virtual environment (Virtual PC, VM Ware, etc.). Here are some bullet points that are worth considering:
- A VHD can dynamically size based on the contents.
- A VHD can be copied (backed up) very easily.
- You can share the VHD with other people on your team.
- You can get back to a known state easily which can be great for testing.
- You get to use drivers allowing you to get full-speed access to video and peripherals.
- You can have a VHD for each client setup the way you want it.
- You can create a VHD for when you go virus hunting on the internet.
- You can mount the VHD under Windows 7 and also host in a virtual machine.
There are also major reasons why booting from a VHD may be counter-productive:
- You cannot hibernate the system when booting from a VHD which can be a pain.
- You don’t get the advantage of having 2 “machines” running at once that you do with Virtual PC etc. so you cannot do machine to machine communication on the same machine this way.
- Disk performance is slightly less.
In summary, it is a great way to get most of the advantages of running a virtual machine with the added advantage that you get full access to the hardware and you run at full-speed (with a slight degradation in disk performance).
