However the energy efficiency initiatives often involve:

1). Virtualization (multiple logical systems running on a single physical system);
2). Running the data centre at higher than traditional temperatures, strict air flow control, novel cooling systems, DC power, and so forth;
3). Using lower power server hardware, often by changing the CPU’s, changing the power supplies, etc.

So what is missing? Decommissioning is what’s missing. A system that ought to be decommissioned often falls into a netherworld of responsibility or priority. Either no one wants to be the one to make that decision, or the priorities are such that working on decommissioning old systems gets continually squeezed out by working on new or ongoing systems.

It is also true that the key metric for a Data Centre Manager is their uptime. They live and die by that number. If a system is down and it shouldn’t be, no matter how well intentioned, the Data Centre looks bad. The metrics for power efficiency are much farther down the importance scale.

Finally, in the Internet age, slow response is also a no-no. Imagine a smartphone client clicks on an icon and nothing happens for a minute. They may well choose another service rather than wait.

Now imagine that all that happened, was the hosting server was sleeping and had to wake up. The impatient world of modern communcations rarely lets this happen without (negative) comment. As a result most servers have all their power saving functions disabled. This allows instant response when called upon, but removes the opportunity to save power under low load conditions.

http://www.informationweek.com/cloud-computing/infrastructure/ny-times-data-center-indictment-misses-b/240007880