External clouds (clouds based in external facilities provided by the new breed of provider) are designed based on very different system assumptions. Because hardware is so cheap, cloud providers' system management practices do not focus on nursing individual pieces of hardware as though they are precious. Instead, hardware is assumed to be inherently frail and subject to failure. And at the scale these providers operate, hardware failure is a common occurrence. For example with hundreds of thousands of disk drives present, failed drives are an everyday occurrence. Motherboard failures that cause an entire machine to go bad happen all the time. At that frequency level of failure, rather than try and preserve individual pieces of hardware, or create specialized environments to preserve a small redundant set of hardware (e.g., SAN environments that can manage dozens or hundreds of drives, but are economically unsustainable at thousands of drive's worth of data), cloud providers build system architectures which are inherently redundant and can tolerate individual hardware failure without consequence.
In this environment, existing system management tools are not appropriate-for the provider or user. So criticizing clouds because you can't use a common system management tools misses the point.
The real issue is whether cloud computing is analogous to virtualization in terms of its benefits. Does cloud computing provide enough benefit to make the inconvenience of using two system management tools worthwhile? With respect to virtualization, the benefits were so obvious and so sizable that IT organizations eagerly embraced it, despite its inconveniences. But what about cloud computing? Will IT groups embrace it despite its inconveniences, the subject of this series of postings? That question turns on the potential TCO of cloud computing, and as I have noted, the case against cloud computing TCO is not nearly as bleak as some people assume. (That's another topic I'll be discussing in the future, as I think it deserves further discussion.)
However, even people who denigrate cloud computing recognize that there are certain use cases in which it shines-transient workload application that do not require significant integration with existing applications. The New York Times EC2 application is a poster child for this use of cloud computing. Given the financial benefit of leveraging EC2 for applications like these, I don't think there's any doubt that IT organizations will accept the pain of using a second system management system. While inconvenient, I predict a future for IT groups that mandates multiple system management tools.
With this, we've come to the last of the main objections to cloud computing. In next week's conclusion, I'll wrap up the series and discuss how I think IT groups will address these objections going forward. I think it's safe to say, however, that the answer is likely to be figuring out how to meet the objections and mitigate them, rather than rejecting the use of cloud computing based on their existence.
Bernard Golden is CEO of consulting firm HyperStratus, which specializes in virtualization, cloud computing and related issues. He is also the author of "Virtualization for Dummies," the best-selling book on virtualization to date.
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