DIMACS TR: 2003-15
Towards an Efficient Cluster-based E-Commerce Server
Authors: Victoria Ungureanu, Michael Katehakis, Benjamin Melamed
ABSTRACT
Cluster-based server architecture combines combines good performance
and low cost, and is commonly used for applications involving high
volume traffic of requests. Essentially, a cluster-based server
consists of a front-end dispatcher and several back-end servers. The
dispatcher receives incoming requests, and then assigns them to
back-end servers, which are responsible with request processing. The
many benefits of cluster-based servers make them a good choice for
e-commerce applications as well. However, applying this type of
architecture to e-commerce applications is hindered by the fact that
an e-commerce cluster has the additional task of validating requests,
i.e. it has to verify that requests comply with contract terms. The
problem is further complicated by the fact that contract terms
may be expressed in terms of dynamic, mutable state. The problem we
are addressing in this paper is how can e-commerce requests be
assigned for processing so that load can be balanced among back-end
servers
and validation of requests can be done in a efficient manner.
To deal with this problem we propose that each stateful contracts is
a-priori assigned to a back-end server, called the base of this
contract, which is responsible for maintaining its state. The
dispatcher assigns requests in the following manner. A request
governed by a stateless contracts is assigned to the least loaded
server. A requests governed
by a stateful contract is assigned to its base whenever the base is
not overloaded. If the base is heavily loaded, the dispatcher assigns
the request to the least loaded server. Only, in the last case the
back-end server needs to contact the base to retrieve the state. To
enable a back-end server to detect when the state is needed, we
propose a contract formulation that explicitly states the contract
type.
Paper Available at:
ftp://dimacs.rutgers.edu/pub/dimacs/TechnicalReports/TechReports/2003/2003-15.ps.gz
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