TaP: Table-Based Prefetching for Storage Caches

TaP is a storage cache sequential prefetching and caching technique to improve the read-ahead cache hit rate and system response time. A unique feature of TaP is the use of a table to detect sequential access patterns in the I/O workload and to dynamically determine the optimum prefetch cache size. When compared to some popular prefetching techniques, TaP gives a better hit rate and response time while using a read cache that is often an order of magnitude smaller than that needed by other techniques. TaP is especially efficient when the I/O workload consists of interleaved requests from various applications, where only some of the applications are accessing their data sequentially.