I’ve just finished reading a post at Vinternal.com about the absence of memory overcommit from Hyper-V 2.0. Microsoft says it’s only good for certain scenario’s (which are rare) and therefore Microsoft doesn’t feel the need for it. I say, and many others, it’s the way around!
My opinion about this issue, is first as a customer I want to have the choice to use it or not to use it. Hyper-V imposes de facto its views to you and myself, as customers. Basically you don’t need that feature, we know at Microsoft what is good for you!
Next, and maybe the most important, virtualization is all about a better utilization of all resources, memory included, and therefore memory overcommit is a must have period!
Look ahead and as Stu mentioned it:
Without the ability to overcommit memory, you could have a cluster of 10 servers all sitting there powered on, each one only using 10% CPU for the 12 hours (or more) per day of non-peak activity during the week. But you won’t be able to consolidate all those VM’s onto 2 or 3 hosts and power the rest off like you can if you have DPM enabled, because with Hyper-V you’ll still need the 10 hosts worth of RAM you’ve provisioned to those VM’s…
My bet Microsoft will finally come up with a similar feature soon or later 🙂