The real challenge will come a year or so later, when the undoubted benefits of cloud computing are manifest. Then the CIO faces the question -- impose disruption on the existing infrastructure or not? On the one hand, there's obvious value in the agility and scalability of the cloud. On the other, all those existing apps in the existing infrastructure have managed to operate for months or years without cloud capabilities, so do they really need it?

It's quite possible that the long-term cloud strategy vis a vis the data center will be to leave it as is and use external resources -- whether an cloud-capable outsourcer (inevitably referred to by trendy cloud cognescenti as a CSP) or an external cloud provider like Amazon, Microsoft, Google or their brethren. Gradually, over time, as the systems running in the data center are replaced by new ones running in some cloud environment, the square footage of the internal center will shrink, until all that is left are critical systems that, for one reason or another, can't be moved outside.

So there you have it -- the con case against private clouds. While the instinctual response by many IT organizations is to assume that a private cloud is the obvious, nay only, way forward, it should be clear that migrating a typical IT environment to a private cloud is not trivial. It may be, as the saying goes, a bridge too far. Certainly, one should not lightly assume that the logic of private clouds is obvious and unassailable.

Next week I'll sum up this series of postings on private clouds and try and provide some guidelines, or action steps, that IT organizations should pursue toward this initiative.

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