Resource Management for Scalable Disconnected Access to Web Services

摘要

Disconnected operation, in which a client accesses a service without relying on network connectivity, is crucial for improving availability, supporting mobility, and providing responsive performance. Because many web services are not cachable, disconnected access to web services may require mobile service code to execute in client caches. Unfortunately, (a) this code is untrusted, (b) this code may have nearly limitless resource demands due to prefetching, and (c) a large number of competing code modules must coexist. Thus, resource management is a key problem both for preventing denial of service attacks and for providing good performance across many services. This paper addresses the feasibility of meeting the resource management needs of an environment where service code is shipped to clients, proxies, or content distribution intermediaries. It first examines the requirements of such a system and then develops a resource-management strategy to meet these requirements by (a) providing isolation across services to prevent denial of service attacks, (b) automatically providing appropriate allocations to different services to provide good global performance, and (c) requiring no hand tuning across a wide range of system configurations and workloads.