Energy saving techniques in datacenters

Number of internet users as well as number of large distributed computer systems has increased dramatically in the last decade. Large distributed computer systems serving lot of users are usually oversized in order to be able to keep up with user demand surges. However in many usage scenarios workload spikes are rare and systems operate on 20%-30% average utilization. Underutilized systems are shown to be power inefficient and different strategies are proposed to tackle this issue. In this paper we present an overview of different power saving techniques that target different types of systems and workloads.