The Multi-Queue Replacement Algorithm for Second Level Buffer Caches

This paper reports our research results that improve second level buffer cache performance. Several previous studies have shown that a good single level cache replacement algorithm such as LRU does not work well with second level buffer caches. Second level buffer caches have different access pattern from first level buffer caches because Accesses to second level buffer caches are actually misses from first level buffer caches. The paper presents our study of second level buffer cache access patterns using four large traces from various servers. We also introduce a new second level buffer cache replacement algorithm called Multi-Queue (MQ). Our trace-driven simulation results show that MQ performs better than all seven tested alternatives. Our implementation on a real storage system validates these results.