申論題

2.Server farms such as Google and Yahoo! Provide enough computer capacity for the highest request rate of the day. Imaging that most of the time these servers operate at only 60% capacity. Assume further that the power does not scale linearly with the load； that is, when the servers are operating at 60% capacity, they consume 90% of maximum power. The servers could be turned off, but they would too long to restart in response to more load. As new system has been proposed that allows for a quick restart but requires 20% of the maximum power while in this "barely alive" state.

2.1 How much power saving would be achieved by turning off 60% of the servers?