I had the great pleasure to converse on twitter along with the exceptional Simon Wardley, a longtime expert and researcher on company innovation, evolution and.. cloud computing. Among the limit of 140 characters, it was quite difficult to convey any sensible concept in such a short space. One of the interesting thing is that it is difficult to provide a sensible comparison between private and public clouds in absence of real numbers. So, since we just finished a research report for a major UK public authority, I will just add my own 2 eurocents and present a summary table of some examples of private, public and dedicated cluster costs:
System $/Core-hour Hopper  $0.018 Montero-Llorente  $0.04 Magellan (overall)  $0.04 Class 1 server/workstation  $0.046 Cornell RedCloud  $0.058 Our estimate $0.06 Amazon cc1.4xl, resv. instance $0.062 Amazon cc1.4xl $0.093 CINN  $0.1
This is of course just a snippet of more than 40 pages; cost includes management and amortization over 3 years for hardware, 5 years for infrastructure. Our own estimate is for a self-managed, self-assembled system with no best practices, while Magellan is a realistic estimate of a median cost for a well-managed and well-procured infrastructure. Hopper is a custom cluster out of commodity hardware and can be considered the best approachable price point for 2011 in terms of cost/core for a private cloud as well. In the paper (that I hope will be published soon) there will be additional details on the actual model, the estimates and the sources for the data. Hope it may be useful for someone.