On-demand multimedia server clustering using dynamic content replication
Citation:
Jonathan Dukes, 'On-demand multimedia server clustering using dynamic content replication', [thesis], Trinity College (Dublin, Ireland). School of Computer Science & Statistics, 2004, pp 191Download Item:
Dukes, Jonathan_TCD-CS-PHD-2004-01.pdf (PDF) 4.293Mb
Abstract:
This thesis examines the provision of on-demand multimedia streaming services using
clusters of commodity PCs. In the proposed HammerHead multimedia server cluster
architecture, a dynamic content replication policy is used to assign non-disjoint subsets
of the presentations in a multimedia archive to cluster nodes. Replicas of selected
presentations can be created on more than one node to achieve load-balancing, increase
performance or increase service availability, while avoiding complete replication of a
multimedia archive on every node. Since the relative demand for the presentations in
a multimedia archive will change over time, the assignment of presentations to nodes
must be periodically reevaluated.
A group communication system is used by the HammerHead architecture to implement
a cluster-aware layer, which maintains the aggregated state of the commodity
stand-alone multimedia server on each cluster node. The aggregated cluster state is
used to redirect client requests to specific nodes and to implement the dynamic content
replication policy. By replicating the aggregated cluster state on each node, the client
redirection task can be shared and the implementation of the dynamic replication policy
can tolerate multiple node failures. The HammerHead architecture proposed in this
thesis is the first multimedia server cluster architecture to combine the use of group
communication with the implementation of a dynamic replication policy.
The Dynamic RePacking content replication policy, which has been used in the
prototype HammerHead server cluster, is a significant improvement of the existing
MMPacking replication policy. Dynamic RePacking separates replication to achieve
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load-balancing from replication to increase the availability of selected multimedia presentations,
allowing increased service availability and performance to be traded against
storage cost. In addition, replicas are assigned to nodes in a manner that allows loadbalancing
to be maintained when nodes fail.
Performance results obtained from a prototype HammerHead cluster and from an
event-driven simulation show that Dynamic RePacking achieves a level of performance
close to that achieved by replicating an entire multimedia archive on every cluster node,
while significantly reducing the required storage capacity. It is believed that this is the
first study to evaluate the performance and behaviour of a dynamic replication policy,
outside a simulation environment.
Author: Dukes, Jonathan
Advisor:
Jones, JeremyQualification name:
Doctor of Philosophy (Ph.D.)Publisher:
Trinity College (Dublin, Ireland). School of Computer Science & StatisticsNote:
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