Replacement Policies for a Distributed Object Caching Service

This paper investigates replacement policies for an object caching service. The replacement policies studied include several previously known schemes, as well as a couple of new schemes that take into account the hierarchical structure of the caching service. Three metrics are used in comparing the replacement policies: cache hit rate - the percentage of requests that were answered from the cache, byte hit rate - the percentage of bytes in replies that were answered from the cache, and access time - average time a client request has to wait for the corresponding reply. Also, unlike most works on cache replacement, this work examines the behavior of the entire system, rather than looking at a single cache at a time.