Ensuring reliability was another concern. With so many commodity hardware servers, "expect to lose one a day," he said. Google decided to "try to deal with that in an automated way. Otherwise, you will have lots of people running around trying to restart servers."
According to Hoelzle, Google has inexpensively built out its computing infrastructure by using thousands of "commodity" servers, instead of fewer high-end, and high-priced, machines. The trick is to make these racks of hardware work together and to ensure that the failure of one machine doesn't derail an operation.