Hyper-V Guest Posts on the TechNet Blogs

If you're one of the many people who are experimenting with virtualization using Hyper-V (and we know you're doing it in a lab environment after taking all the necessary precautions and creating backups, right?) Microsoft blogger Tony Soper is providing an interesting opportunity for you to share what you've learned.

If you have some Hyper-V knowledge you'd like to share, you can send it to Tony by following the instructions on his blog.

The first reader to take Tony up on his offer was Jeremy Hagan, who wrote about how to shrink a VHD file. Jeremy's basic dilemma went something like this:

One problem I have had when trying to do my first round of P2Vs for my Hyper-V implementation that I didn’t notice in testing is that you can’t size the VHD of the VM smaller than the corresponding physical disk of the original machine.  Since it is best practice to have one LUN per VM and it is also best practice to have fixed VHDs, this can cause a lot of wasted SAN space.

And his solution revolves around this:

What I decided I needed to do was to P2V each machine to a sufficiently large scratch LUN, then shrink down the VHDs to be the size I wanted then migrate the VM off the scratch LUN to the desired LUN.  Easy right?  Well maybe not.  After much searching I have managed to come up with a recipe for doing this.