Understanding Web traffic characteristics is key to improving the performance and scalability of the Web. In this article Web proxy workloads from different levels of a caching hierarchy are used to understand how the workload characteristics change across different levels of a caching hierarchy. The main observations of this study are that HTML and image documents account for 95 percent of the documents seen in the workload; the distribution of transfer sizes of documents is heavy-tailed, with the tails becoming heavier as one moves up the caching hierarchy ; the popularity profile of documents does not precisely follow the Zipf distribution; one-timers account for approximately 70 percent of the documents referenced; concentration of references is less at proxy caches than at servers, and concentration of references diminishes as one moves up the caching hierarchy; and the modification rate is higher at higher-level proxies.

This article reports on enterprises exploiting large shared resource pools in data center environments to lower their infrastructure and management costs. Environments like these may have tens, hundreds, or even thousands of server resources. Capacity management for resource pools determines how many resources are needed to support a given set of application workloads, which applications must be assigned to each resource, and per-application scheduling parameters to ensure appropriate sharing and isolation for the applications