PFC: Transparent Optimization of Existing Prefetching Strategies for Multi-level Storage Systems

The multi-level storage architecture has been widely adopted in servers and data centers. However, while prefetching has been shown as a crucial technique to ex-ploit the sequentiality in accesses common for such systems and hide the increasing relative cost of disk I/O, existing multi-level storage studies have focused mostly on cache re-placement strategies. In this paper, we show that prefetch-ing algorithms designed for single-level systems may have their limitations magnified when applied to multi-level sys-tems. Overly conservative prefetching will not be able to effectively use the lower-level cache space, while overly aggressive prefetching will be compounded across levels and generate large amounts of wasted prefetch. We take an innovative approach to this problem: rather than de