 |
| Cluster |
Computer cluster is called a group of computers working toward a common goal. These computers clustered hardware, networking communication and software to work together as if they were a single system. There are many attractive reasons for these groups, but the main one isable to perform the information processing more efficiently and quickly as if it were a single system. Generally, a cluster works on alocal area network (LAN) and allows for efficient communication, although the machines are in an area close physical. A greater understanding of the concept is called the grid, where the goal is the same, but involves clusters of computers connected by wide area networks (WAN). Some authors consider the grid as a cluster of clusters in a sense 'global'. While more and more technology and costs allow these approaches, efforts and complexity of using tens or hundreds(sometimes thousands) is very large. without However, the advantages in computation time makes even so, this type of solutions for high performance computing (HPC, high performance computing) are considered very attractive and constantly evolving.
Simply put, cluster is a group of multiple computers connected by a network of the common desktop. Clusters are usually employed to improve performance and / or the availability of individual computers of comparable speed and availability.
A cluster is expected to present combinations of the following services:
● High Performance :A high performance cluster is a set of computers that is designed to give high performance in terms of computing power.
● High Availability :A set of two or more machines that are characterized by having a series of shared services and by constantly monitoring each other.
● Load Balancing:A load balancing cluster or adaptive computing is composed of one or more computers (called nodes) that act as cluster frontend, and involved in distributing the service requests received by the cluster, other cluster computers that form the back-end of it.
● Scalability :Scalability is the desirable property of a system, a network or a process that indicates its ability to either handle the continued growth of job smoothly, or to be prepared to get bigger without losing quality of services offered
The construction of the computers of the cluster is easier and cheaper because of its flexibility: they can all have the same hardware configuration and operating system (Homogeneous cluster), but yield different architectures and operating systems heterogeneous., making it easier and cheaper construction.
it is necessary to provide a cluster management system, which is responsible for
Classification of the Clusters
The term cluster has different connotations for different groups of persons. The types of clusters, established on the basis of the use that of to the clusters and the services that offer, they determine the meaning of the term for the group that uses it. The clusters can qualify with base in his characteristics. They can be had clusters of high performance (HPC - High Performance Clusters), clusters of high availability (THERE IS - High Availability) or clusters of high efficiency (HT - High Throughput).
High Performance (HPC): They are clusters in which there are executed tasks that they need of great computational capacity, big quantities of memory, or both simultaneously. To carry out these tasks can compromise the resources of the cluster for lengths To carry out these tasks can compromise the resources of the cluster for long periods of time.
High Availability (HA) clusters are intended design is to provide availability and reliability. Theseclusters are trying to provide maximum availability of the services they offer. The reliability is provided by software that detects failures and allows them recover from, while in hardwareprevents having a single point of failure.
High Efficiency (HT): These are clusters of design aim is to run as many tasks in the shortest time possible. There is data independence between individual tasks. The delay between cluster nodes is not considered a big problem.
