Scott Drummonds on Virtualization

Hyper-V's Lack of Memory Over-commit

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I find it interesting that one day after I wrote about memory over-commitment in vSphere, Greg Shields wrote about the lack of memory over-commitment in Hyper-V.  In today’s short blog entry, I want provide one paragraph that Greg’s article currently lacks:

While memory over-subscription is a critical feature for production environments, balancing the demands of heterogenous applications of varying demands in a resource starved environment is difficult.  Without guidance from administrators on the relative importance of the virtual machines running these applications, a hypervisor will be forced to make arbitrary decisions in assigning limited resources.  Effective use of over-commitment requires a sound resource control system.  The only product on the market that does this well is VMware vSphere.

Both Greg and my articles only talked of memory over-commitment, but the rules apply for CPU over-commitment, too.  Microsoft will realize how important resource controls are somewhere between year two and five of their product’s life.  I can only imagine where vSphere will be by then.