You can of course read new accounts of using VMs for server consolidation on a daily basis. Here’s a particularly dramatic example.

This article relays (HP CEO) Mark Hurd’s comments in a recent keynote:

He said that HP had more than 700 datamarts, 87 datacenters, 20 petabytes of non-shared storage, and were running on 5,000 applications. Since his arrival in 2004, the company has reduced the number of datacenters to three and consolidated 9,000 servers “by virtualizing and blading half the infrastructure.”

Noting that “virtualization is a big deal to us,” Hurd also said HP has cut the number of apps its uses to 1,400, and can now “provide real-time enterprise financial information, supply chain information, and customer information across the enterprise.”

What is most impressive to me is how HP’s internal users survived this transition. That’s quite a lot of infrastructure change over the course of three years, especially considering the application changes. It’s unwise to speculate without more information, but I bet it was not easy.