Cluster computing introduction

1. CLUSTER COMPUTING
Presented by :
Shreeraj Khatiwada
Msc. Computer Science
NCIT College, Lalitpur

2. OUTLINES:
 Introduction
 Objective/Design requirements
 Cluster Configuration
 Cluster Methods
 Clusters Computer Architecture
 Implementation: Blade servers
 Clusters compared to SMP

3. INTRODUCTION:
 Super, Mainframe computers are not cost effective.
 Cluster is a widely used term meaning multiple independent computers
combined to work in coordinated fashion to process applications 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.
 Whole computers working together as a unified computing resources
can create illusion of being one machine.
 The term whole computer means a system that can run on its own, apart
from the cluster; each computer in a cluster is typically referred to as a
node.
 Composed of many commodity computers , linked together by a high-
speed dedicated network.

4. OBJECTIVE/DESIGN REQUIREMENTS:
 Absolute Scalability
 Incremental Scalability
 High Availability
 Superior Price/ Performance

5. CLUSTER CONFIGURATION:
High Availability Clusters:
 These clusters are designed to provide uninterrupted availability of data or
service (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 missing node.
 High availability clusters implementations are best for mission-critical
applications or databases, mail, file and print, web or application servers.
Load Balancing Clusters:
 This type of cluster distributes the incoming requests for resources or content
among multiple nodes running the same program or having the same content.
 Every node in the cluster is able to handle requests for the same content or
application.
 Middleware mechanisms need to recognize that services can appear on
different members of cluster and may migrate from one member to another.
 Almost all load balancing clusters are HA clusters.
 This type of distribution is typically seen in a web hosting environment.

6. 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.

7. CLUSTERING METHODS:
Some clustering methods are:
Passive Standby:
 Older method.
 A secondary server takes over in case of
primary server failure.
 Easy to implement.
 High cost because the secondary server is
unavailable for the other processing tasks.
 Heartbeat message.

8. Separate Servers:
 Separate servers have their own disks. Data is continuously copied from primary to
secondary server.
 High performance as well as high availability
 Scheduling software needed for load balancing
 High availability, Communication overhead

9. Shared nothing and shared Memory:
Reduce the communication overhead.
Servers connected to common disk.
Shared Nothing: common disks are partitioned into volumes, and each volume
owned by a single computer.
Shared Disk: Multiple computers share the same disks at the same time, so
that each computer has access to all the volumes on all of the disks.

10. CLUSTER COMPUTER ARCHITECTURE:

11.  Individual computers are connected by some high-speed LAN or switch hardware.
 Each computer is capable of operating independently.
 Middleware layer of software is installed in each computer to enable cluster operation.
 The middleware provides a unified system image to the user, known as a single-system
image.
 The middleware is responsible for providing high availability, by means of load balancing
and responding to failures in individual components. Following are the desirable cluster
middleware services and functions:
Single entry point
Single file hierarchy
Single control point
Single virtual networking (any node can access any other point )
Single memory space
Single job-management system
Single user interface
Single I/O space
Single process space
Checkpointing (saves the process state, recovery after failure)
Process migration (load balancing)

12.  The last four items in the preceding list
enhance the availability of the cluster.
 Others are concerned with providing a single
system image.
Implementation: Blade Servers
 Is a server architecture that houses multiple
server modules (‘blades’) in a single chassis.
 Used in data centres.
 Increase server density, lowers powers and
cooling costs, ease server expansion and

13. Ethernet configuration for Massive Blade Server Site

14. CLUSTERS COMPARED TO SMP:
 Both clusters and symmetric multiprocessors
provide a configuration with multiple
processors to support high-demand
applications.
 Both solutions are commercially available.
 SMP: the processing of programs by multiple
processors that share a common OS and
memory. Whereas , in clusters individual
systems are tied together.
 The aim of SMP is time saving and of cluster
computing is high availability.

15. THANK YOU!