Unless you were on another planet for the last 4 weeks, you could not have missed Microsoft rambling posts here, here, here and here called Hypervisor Footprint Debate. As usual a lot of misunderstandings and marketing bla bla. The fact is that Microsoft doesn’t have the versatility of VMware and cannot get out of its monolithic OSes period!
We’ve consistently taken the position that a smaller hypervisor is inherently better and we’ve found that most people agree with us, including Microsoft’s Technical Fellow, Mark Russinovich (see his presentation from Burton Group’s Catalyst Conference in July.) The reasoning is that every line of code unavoidably adds reliability and security risks. Microsoft has cited those same benefits of “smaller attack surface” from code size reduction as the motivation for their slimmed down Server Core and Hyper-V Server alternatives. We don’t know how many lines of code are in a Hyper-V system, so we use the installed disk footprint — the size of the installed files needed to support virtual machines — as a reasonable proxy for lines of code. In calculating hypervisor disk footprints we need to follow a few rules to ensure consistency:
Read the full response here. A unique one that clarify it all.