The Taub Faculty of Computer Science Events and Talks

In cooperative storage caching, clients may access blocks directly from each other's caches. Previous studies treated all the cooperating caches as a single pool, maximizing overall system performance at the price of possibly degraded performance for individual clients. In light of the popularity of many P2P mechanisms, we re-evaluate the concept of cooperative caching, considering selfish clients that cooperate only if they benefit from the interaction. This is the first study that considers selfish clients in the context of cooperative storage caching. We present and analyze several novel cooperative caching approaches for varying degrees of client selfishness. These approaches are based on concepts borrowed from distributed storage systems, peer-to-peer systems, and our experience with state-of-the-art multilevel caching mechanisms. Our evaluation focuses on the performance as well as the energy requirements and operational costs of these approaches, on a wide range of systems and two workload domains. Our results provide answers to two basic questions: When should clients cooperate, and how?