Storage Management For Web Proxies

Today, caching web proxies use general-purpose file systems to store web objects. Proxies, e.g., Squid or Apache, when running on a UNIX system, typically use the standard UNIX file system (UFS) for this purpose. UFS was designed for research and engineering environments, which have different characteristics from that of a caching web proxy. Some of the differences are high temporal locality, relaxed persistence requirements, and a different read/write ratio. In this paper, we characterize the web proxy workload, describe the design of Hummingbird, a light-weight file system for web proxies, and present performance measurements of Hummingbird. Hummingbird has two distinguishing features: it separates object naming and storage locality through direct application-provided hints, and its clients are compiled with a linked library interface for memory sharing. When we simulated the Squid proxy, Hummingbird achieves document request throughput 2.3-9.4 times larger than with several different versions of UFS. Our experimental results are verified within the Polygraph proxy benchmarking environment.