A new study says that 30 percent of all physical servers in data centres are comatose, or are using energy but aren’t doing anything useful.
According to Jonathan Koomey, a research fellow at Stanford University, the problem has been around for a while, as the percentage hasn’t changed since 2008.
He used data collected by TSO Logic, an energy efficiency software vendor, from nearly 4,000 physical servers in customer data centres. They decided that a server is considered comatose if it hasn’t done anything for at least six months, which would be an interesting definition if applied to a human.
Koomey said it was not a technical matter as much as a management problem but more work is needed to confirm or refute those numbers.
IDC estimated the number of physical servers worldwide last year at 41.4 million; that figure is expected to grow to 42.8 million by the end of this year.
A study last year by the Natural Resources Defence Council (NRDC), with the help of major vendors, estimated that in the U.S. alone data centres used 91 billion kilowatt-hours of electrical energy in 2013.
That use is expected to increase 53 percent by 2020.
It estimated that electrical usage could be reduced by 40 percent by getting rid of zombie servers and improving energy efficiency. That figure represents only half of the technically possible reduction in energy use.
It is the smaller data centres which were the problem rather than the big clouds.