Grid computing is a service for sharing computer power and data storage capacity over the internet. It is the use of parallel processing to speed up database performance. Grid computing forms a global network of computers that can operate as one vast computational resource. Computers and instruments connected to the grid do not only share information but computing power and resources like disk storage and software applications. Grid technology is used for executing science, engineering, industrial and commercial applications such as drug design, aerospace modeling, crash simulations, high energy physics,electric CAD, ray tracing, data mining and so on. The grid is not a cluster, the resource allocation is performed by a centralized resource manager and all nodes corporately work together as a single unified resource. This is very useful because incase one node fails the other nodes will still work and this means that the grid will work regardless. There are no single failure spots. To the user the grid acts as a single,huge and powerful computer.