A timely snapshot -- see the full article for more details
Google doesn't reveal exactly how many servers it has, but I'd estimate it's easily in the hundreds of thousands. It puts 40 servers in each rack, Dean said, and by one reckoning, Google has 36 data centers across the globe. With 150 racks per data center, that would mean Google has more than 200,000 servers, and I'd guess it's far beyond that and growing every day.
Regardless of the true numbers, it's fascinating what Google has accomplished, in part by largely ignoring much of the conventional computing industry. Where even massive data centers such as the New York Stock Exchange or airline reservation systems use a lot of mainstream servers and software, Google largely builds its own technology.