Decrepol: a Decentralized Replication Policy for Web Documents
Author: Paul Zijlmans
Source: Masters thesis, Vrije Universiteit, August 2006.
Abstract
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The current size of the Internet makes it impossible to host major Web
sites on a single server. Replication can improve both the
availability and the performance of a Web hosting service. Current
replication policies heavily rely on the origin server. Therefore,
this thesis presents Decrepol, a decentralized replication policy for
Web documents that assumes the origin server to be unavailable most of
the time. First, we present a replication policy that achieves full
replication and is structured following epidemic protocols. With this
policy we are able to spread notifications across 128 replica servers
in about 5 gossip rounds. Next, we present a decentralized replication
policy that allows for controlled partial replication. We create two
versions of the partial replication policy. The first one is based on
epidemic protocols and is an extented version of the full replication
policy. However, in this policy locating replicas becomes a
problem. Therefore, we also present an improved unstructured version
that facilitates locating content. With this version, inserting and
retrieving documents requires traversing about three hops. The second
version is based on structured peer-to-peer systems. Inserts take
about four hops, retrieves only two hops if we cache document
searches. We show that it is possible to create an unstructured
partial replication policy that performs almost identically to a
structured one and thus can be an interesting alternative.
Keywords: Replication policy, Web hosting, Peer-to-peer, Decentralization. |
Download
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The thesis, in PDF (558,591 bytes). |
Bibtex Entry
@MastersThesis{,
author = {Paul Zijlmans},
title = {Decrepol: a Decentralized Replication Policy
for Web Documents},
school = {Vrije Universiteit},
address = {Amsterdam, The Netherlands},
year = {2006},
month = aug,
note = {\url{http://www.globule.org/publi/DDRPWD_master2006.html}}
}
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