What is Computer Cluster

Computer cluster is a collection of computers connected as a grid to perform special tasks. Rather than using one high performed computer, collection of computers so called cluster provides considerable advantages through high availability and performance. Computer cluster can be specified according to different criteria. Here is a summary of classification of clusters.

1. On Technical view

a. Software clusters

i. OS level -Operating System will manage and process the cluster activities. These types of clusters are heavily used in performance required computers. Since OS controlling computer resources like memory, storage by applying suitable resource to suitable occasion OS level clusters provide more performance needs.

a. Active-Passive -When one server goes down another will take care of process.

b. Active-Active-all the servers online and share the resources and work load.

ii. Software level-Special software package base on the application will perform the management of the cluster.These types of cluster can provide specific feature which is unique to that product. Mainly database products and Application servers provide software level clusters. Ex Oracle RAC, MYSQL Cluster, JBOSS, WEBSPHERE clusters

              
b. Hardware Clusters

Hardware device will manage the computer cluster. Ex load balancers.

2. On Purpose

           
a. Highly available –at least one server will serve work when others go down.
b. Load balanced - Load will be balanced between two or more nodes. Working on separate server

c. High performed - Process will be shared by nodes.

In general we combine these clusters to achieve all the benefits giving by three types.