From The Information Factories by George Gilder of Wired Magazine
"The facility in The Dalles is only the latest and most advanced of about two dozen Google data centers, which stretch from Silicon Valley to Dublin. All told, it's a staggering collection of hardware, whose constituent servers number 450,000, according to the lowest estimate.
The extended Googleplex comprises an estimated 200 petabytes of hard disk storage – enough to copy the Net's entire sprawling cornucopia dozens of times – and four petabytes of RAM. To handle the current load of 100 million queries a day, its collective input-output bandwidth must be in the neighborhood of 3 petabits per second."