03-12-2012, 05:49 PM
CLUSTER COMPUTING
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Introduction
A cluster is a type of parallel or distributed processing system, which consists of a collection of interconnected stand alone computers co - operatively working together as a single, integrated computing resource. This cluster of computers share common network characteristics like the same namespace and it is available to other computers on the network as a single resource .These computers are linked together using high-speed network interfaces between themselves and the actual bind in together of the all the individual computers in the cluster is performed by the operating system and the software used
Computing is an evolutionary process. Five generations of development history— with each generation improving on the previous one’s technology, architecture, software, applications, and representative systems—make that clear. As part of this evolution, computing requirements driven by applications have always outpaced the available technology. So system designers have always needed to seek faster, more cost effective computer systems. Parallel and distributed computing provides the best solution, by offering computing power that greatly exceeds the technological limitations of single processor systems. Unfortunately, although the parallel and distributed computing concept has been with us for over three decades , the high cost of multiprocessor systems has blocked commercial success so far. Today, a wide range of applications are hungry for higher computing power, and even though single processor PCs and workstations now can provide extremely fast processing; the even faster execution that multiple processors can achieve by working concurrently is still needed. Now, finally costs are falling as well. Networked clusters of commodity PCs and workstations using off-the-shelf processors and communIcation platform such as Myrinet, Fast Ethernet, and Gigabit Ethernet are becoming increasingly cost effective and popular. This concept, known as cluster computing, will surely continue to flourish: clusters can provide enormous computing power that a pool of users can share or that can be collectively used to solve a single application. In addition, clusters do not incur a very high cost, a factor that led to the sad demise of massively parallel machines.
Clusters, built using commodity-off-the-shelf (COTS) hardware components and free, or commonly used, software, are playing a major role in solving large-scale science, engineering, and commercial applications. Cluster computing has emerged as a result of the convergence of several trends, including the availability of in expensive high performance microprocessors and high speed networks, the development of standard software tools for high performance distributed computing, and the increasing need of computing power for computational science and commercial applications.
Cluster History
The first commodity clustering product was ARC net, developed by Data point in 1977. ARCnet wasn't commercial success and clustering didn't really take off until DEC released their VAXcluster product in the 1980s for the VAX/VMS operating system. The ARCnet and VAXcluster products not only supported parallel computing, but also shared file systems and peripheral devices. They were supposed to give you the advantage of parallel processing while maintaining data reliability and uniqueness. VAXcluster, now VMScluster, is still available on Open VMS systems from HP running on Alpha and Itanium systems. The history of cluster computing is intimately tied up with the evolution of networking technology. As networking technology has become cheaper and faster, cluster computers have become significantly more attractive.
How To Run Applications Faster?
There are 3 ways to improve performance:
Work Harder
Work Smarter
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Era Of Computing
Rapid technical advances
•the recent advances in VLSI technology
•software technology
•grand challenge applications have become the main driving force
•Parallel computing
Why Clusters ?
The question may arise why clusters are designed and built when perfectly good commercial supercomputers are available on the market. The answer is that the latter is expensive. Clusters are surprisingly powerful. The supercomputer has come to play a larger role in business applications. Commercial products have their place, and there are perfectly good reasons to buy a commercially produced super computer . However, many who have a need to harness supercomputing power don‟t buy supercomputers because they can‟t afford them. Also it is impossible to upgrade them . Clusters, On the other hand, are cheap and easy way to take individual components and combine them into a single supercomputer. In some areas of research clusters are actually faster than commercial supercomputer. Clusters also have the distinct advantage in that they are simple to build using components available from hundreds of sources. The most obvious benefit of clusters, and the most compelling reason for the growth in their use, is that they have significantly reduced the cost of processing power. This reduction in the cost of entry to high-power computing (HPC) has been due to co modification of both hardware and software over the last 10 years particularly. All the components of computers have dropped dramatically in that time. The components critical to the development of low cost clusters are:
1. Processors - commodity processors are now capable of computational power previously reserved for supercomputers.
2. Memory - the memory used by these processors has dropped in cost right with the processors.
3. Networking Components - the most recent group of products to experience co modification and dramatic cost decreases is networking hardware. High- Speed networks can now be assembled with these products for a fraction of the cost necessary only a few years ago.
4. Motherboards, busses, and other sub-systems – All of these have become commodity products, allowing the assembly of affordable computers from off the shelf components