CLUSTER COMPUTING
Content
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Introduction
Cluster Categorization
Cluster Component
How Does It Work?
Cluster Benefits
Cluster Features
Cluster Application
Limitations
Conclusion
INTRODUCTION
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Cluster is a widely used term meaning
independent computers combined into a unified
system through software and networking
• Clusters are typically used for High
Availability (HA) for greater reliability or High
Performance Computing (HPC) to provide
greater computational power than a single
computer can provide.
• Clusters are composed of many commodity
Cluster Categorization
• High-availability (HA) clusters
• Load balancing clusters
• High-performance (HPC) clusters
• Grid Cluster
High Availability or Failover Clusters
 These clusters are designed to provide uninterrupted availability
of data or services (typically web services) to the end-user
community.
 if a node fails, the service can be restored without affecting the
availability of the services provided by the cluster. While the
application will still be available, there will be a performance
drop due to the missing node.
 The purpose of these clusters is to ensure that a single instance of
an application is only ever running on one cluster member at a
time but if and when that cluster member is no longer available,
the application will failover to another cluster member.
• High-availability clusters implementations are
best for mission-critical applications or
databases, mail, file and print, web, or
application servers.
Load Balancing Cluster
 This type of cluster distributes incoming requests for resources or
content among multiple nodes running the same programs or
having the same content.
 Both the high availability and load-balancing cluster technologies
can be combined to increase the reliability, availability, and
scalability of application and data resources that are widely
deployed for web, mail, news, or FTP services.
 Every node in the cluster is able to handle requests for the same
content or application.
 This type of distribution is typically seen in a web-hosting
environment.
Load Balancing Cluster Diagram
Parallel/Distributed Processing Clusters
 parallel processing was performed by multiple
processors in a specially designed parallel
computer. These are systems in which multiple
processors share a single memory and bus
interface within a single computer.
These types of cluster increase availability,
performance, and scalability for applications,
particularly computationally or data intensive
tasks.
Cluster Component
The basic building blocks of clusters are broken
down into multiple categories:
1. Cluster Nodes
2. Cluster Network
3. Network Characterization
How Does It Work?
 A user submits a job to the head node. The job
identifies the application to run on the cluster.
The job scheduler on the head node assigns each
task defined by the job to a node and then starts
each application instance on the assigned node.
Results from each of the application instances are
returned to the client via files or databases.
Cluster Computing Features
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Network technologies
Network Types
Communication Protocols
Operating system
Single System Image (SSI)
Quorum
CLUSTER BENEFITS
The main benefits of clusters are:
1. Availability
2. Performance
3. Scalability
 These benefits map to needs of today's
enterprise
business, education, military and
scientific community infrastructures.
Cluster Application
There are three primary categories of
applications that use parallel clusters:
1. Compute Intensive Application.
2. Data or I/O Intensive Applications.
3. Transaction Intensive Applications.
LIMITATIONS
• Typically latency is very high and bandwidth
relatively low.
• Currently there is very little software support for
treating a cluster as a single system.
• Problems exist in the interactions between mixed
application workloads on a single time-shared
computer
CONCLUSION
Cluster computing has become a major part of many
research programs because the price to performance
ratio of commodity clusters is very good. Also, because
the nodes in a cluster are clones, there is no single point
of failure, which enhances the reliability to the cluster.
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