Who Has the Most Web Servers?

Google: The search giant's server count has long been the focus of speculation. The company doesn't release numbers, but a recent report from energy expert Jonathan Koomey estimated that Google had 900,000 servers, based on an extrapolation from data Google provided on its total energy usage. Google's recently revealed container data center holds more than 45,000 servers, and that's a single facility built in 2005.

Amazon: It runs the world's largest online store and one of the world's largest cloud computing operations. Amazon says very little about its data center operations, but we know that it bought $86 million in servers from Rackable in 2008, and stores 40 billion objects in its S3 storage service. A 2009 analysis by Randy Bias estimates that 40,000 servers are dedicated to running Amazon Web Services' EC2.

Yahoo: While its data center infrastructure isn't quite as enormous as those for Google and Microsoft, the third major search portal likely has more than 100,000 servers in operation to support its large free hosting operation as well as its paid hosting service and Yahoo Stores.

GoDaddy: It's the world's largest domain registrar with more than 35 million domains under management, but effective cross-selling of its hosting plans has also made GoDaddy one of the largest shared hosting operations in the world. It's infrastructure is probably similar in scope to that of 1&1 Internet.

HP/EDS: While server "ownership" is less distinct with system integrators, EDS has an enormous data center operation. Company documents (PDF) say EDS is managing 380,000 servers in 180 data centers. (Thanks, Bruce for the link).

IBM: With more than 8 million square feet of data center space, IBM also houses an enormous number of servers in its data centers, both for itself and its customers.