Jerome Wendt’s opinion piece in today’s ComputerWorld is a short, sweet and to-the-point summary of the downsides of consolidating on vertical servers – The downsides to server virtualization. Wendt’s first (and I think the most important point) is licensing.
“Software Licensing. Larger servers include more CPUs that each has more processing power. However, this can translate into increased software licensing costs. I just spoke to one company that found out too late that their software licensing costs were tied to the number of CPUs and their increased processing power in their new hardware. This surprise offset many of the financial benefits that consolidation was supposed to provide and may even negate them.”
While software licensing and server complexity are both typical in any environment, both are items that should have special consideration in a virtualized environment. In terms of single point of failure, I would say that you have a single server holding everything together. And, that’s not likely to happen.