May 10, 2013
Interschool Lab (750 CEPSR)
Hosted by: Columbia University Joint CS/EE Networking Seminar Series
Speaker: Prof. Mor Harchol-Balter , Associate Professor (Computer Science Dept., Carnegie Mellon University)
Energy costs for data centers continue to rise, already exceeding ten billion dollars yearly. Sadly much of this power is wasted. Server are only busy 10-30% of the time, but they are often left on, while idle, utilizing 60% of more of peak power while in the idle state. The obvious solution is dynamic power management: turning servers off, or re-purposing them, when idle. The drawback is a prohibitive "setup cost" to get servers back "on." The purpose of this talk is to understand the effect of the "setup cost" and whether dynamic power management makes sense.
We first turn to theory and study the effect of setup cost in an M/M/k queue. We present the first analysis of the M/M/k/setup queueing system. We do this by introducing a new technique for analyzing infinite, repeating, continuous-time Markov chains, which we call Recursive Renewal Reward (RRR).
We then turn to practice, where we implement and evaluate dynamic power management in a multi-tier data center with key-value store workload, reminiscent of Facebook or Amazon. We propose a new dynamic algorithm, AutoScale, which is ideally suited to the case of unpredictable, time-varying load, and we show that AutoScale dramatically reduces power in data centers.
Joint work with: Anshul Gandhi, Alan Scheller-Wolf, Sherwin Doroudi, and Mike Kozuch.
Mor Harchol-Balter is an Associate Professor in Computer Science at Carnegie Mellon University. From 2008-2011, she served as the Associate Department Head for Computer Science. She received her doctorate in Computer Science at U.C. Berkeley under the direction of Manuel Blum. She is a recipient of the McCandless Chair, the NSF CAREER award, the NSF Postdoctoral Fellowship in the Mathematical Sciences, multiple best paper awards, and several teaching awards, including the Herbert A. Simon Award for Teaching Excellence. She is heavily involved in the ACM SIGMETRICS performance research community, where she served as Technical Program Chair for Sigmetrics 2007 and is General Chair for Sigmetrics 2013.