One of the most frequently asked questions about Cloud Computing regard the necessity of hypervisors. I believe most reasonable individuals agree that while they are not absolutley NECESSARY, for most instances, they certainly make CC economically feasible.

My intent here, is not to run down the rathole of "which is the best hypervisor?" The answer to that, as well as most emotionally-charges questions is "it depends." My intent is, however, to examine how the needs of Cloud Computing may differ from those of the traditional Data Center where server (and eventually client)virtualization is concerned.

There is no question of who rules the Corporate Data Center. While VMware's absolute dominance of overall share has been dented (in part by wide deployments like Amazon, which can skew the statistics) drilling down by excluding Public or Government Clouds, will show VMware ESX (if various versions) as the 800 lb. Gorilla of server virtualization inside the firewalls.

Why then would Amazon choose to go with a wild card like Open Source Xen ? The answer is simply, because the needs of a hugely scalable publicly-available multi-tenant platform are far different then even the largest in-house Corporate Data Center, even if its owners choose to call it a "Private Cloud."

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Read the rest at the Cloud Slam Event blog.