Superset: a non-uniform replica placement strategy towards perfect load balance and fine-grained power proportionality

Abstract

Load balance and power proportionality are both important aspects in constructing high-performance and cost-effective distributed storage systems. However, traditional replica placement strategies which provide load balance usually produce scattered replica layouts, thus disabling power proportionality, while recent strategies that enable power proportionality are typically based on uniform replication, thus compromising the ability of load balance. In this article, we introduce Superset (an organized non-uniform replica placement strategy) which takes both load balance and power proportionality into consideration. The main idea is to partition the whole system into several uniform replication based subsystems with the accommodated file subsets satisfying the `superset' condition. We proved Superset to be theoretically effective, and conducted a series of simulations with real-world distributions of data popularity. Our results show that, compared to state of the art solutions, Superset consumes less energy to fulfill the same performance requirement while offers higher performance subject to the same energy consumption constraint.