The effect of server energy proportionality on data center power oversubscription

摘要

Modern data centers improve resource utilization with power oversubscription. The power hierarchy in a data center is oversubscribed by installing more servers than allowed by the power budget based on server peak power consumption. Power oversubscription is possible due to the statistically low likelihood of simultaneous peak power operation of multiple servers. As future servers become more energy proportional, the opportunity for greater power oversubscription increases. The challenge is to quantify the level of oversubscription that can be attained. In this paper, we quantify the level of oversubscription possible for a given acceptable probability of power overload for servers characterized by energy proportionality metric and workload distribution. We develop a theoretical framework to characterize and predict the relationship between server energy proportionality and power oversubscription. We verify our framework through an extensive empirical study using publicly available SPECpower benchmark data for over 500 server models and publicly available Google cluster utilization data. Using our framework, a data center operator can predict the additional power oversubscription possible when replacing existing servers with a newer model of more energy proportional servers.