Analysis of Web caching architectures: hierarchical and distributed caching

Cache cooperation improves the performance of isolated caches, especially for caches with small cache populations. To make caches cooperate on a large scale and effectively increase the cache population, several caches are usually federated in caching architectures. We discuss and compare the performance of different caching architectures. In particular, we consider hierarchical and distributed caching. We derive analytical models to study important performance parameters of hierarchical and distributed caching, i.e., client's perceived latency, bandwidth usage, load in the caches, and disk space usage. Additionally, we consider a hybrid caching architecture that combines hierarchical caching with distributed caching at every level of a caching hierarchy. We evaluate the performance of a hybrid scheme and determine the optimal number of caches that should cooperate at each caching level to minimize client's retrieval latency.