Here’s an excerpt:
If you virtualize 100 percent of your physical servers today then you will be running more operating system instances than you started with. The physical and environmental footprint has changed but you still need to monitor, patch, secure, backup and license the virtualized servers and now the host servers as well. Requirements such as high availability further increase infrastructure costs. Yet the publicity of energy and space savings has created a mindset that virtualized servers are cheap. Consolidation through virtualization therefore is only a partial answer to becoming more IT efficient.