2 research outputs found
Optimization inWeb Caching: Cache Management, Capacity Planning, and Content Naming
Caching is fundamental to performance in distributed information retrieval systems
such as the World Wide Web. This thesis introduces novel techniques for optimizing performance
and cost-effectiveness in Web cache hierarchies.
When requests are served by nearby caches rather than distant servers, server loads and
network traffic decrease and transactions are faster. Cache system design and management,
however, face extraordinary challenges in loosely-organized environments like the Web,
where the many components involved in content creation, transport, and consumption are
owned and administered by different entities. Such environments call for decentralized
algorithms in which stakeholders act on local information and private preferences.
In this thesis I consider problems of optimally designing new Web cache hierarchies
and optimizing existing ones. The methods I introduce span the Web from point of content
creation to point of consumption: I quantify the impact of content-naming practices on
cache performance; present techniques for variable-quality-of-service cache management;
describe how a decentralized algorithm can compute economically-optimal cache sizes in
a branching two-level cache hierarchy; and introduce a new protocol extension that eliminates
redundant data transfers and allows “dynamic” content to be cached consistently.
To evaluate several of my new methods, I conducted trace-driven simulations on an
unprecedented scale. This in turn required novel workload measurement methods and efficient
new characterization and simulation techniques. The performance benefits of my proposed
protocol extension are evaluated using two extraordinarily large and detailed workload
traces collected in a traditional corporate network environment and an unconventional
thin-client system.
My empirical research follows a simple but powerful paradigm: measure on a large
scale an important production environment’s exogenous workload; identify performance
bounds inherent in the workload, independent of the system currently serving it; identify
gaps between actual and potential performance in the environment under study; and finally
devise ways to close these gaps through component modifications or through improved
inter-component integration. This approach may be applicable to a wide range of Web
services as they mature.Ph.D.Computer Science and EngineeringUniversity of Michiganhttp://deepblue.lib.umich.edu/bitstream/2027.42/90029/1/kelly-optimization_web_caching.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/90029/2/kelly-optimization_web_caching.ps.bz