In last few years, rapidly increasing businesses and their capabilities & capacities in terms of computing has grown in very large scale. To manage business requirements High performance computing with very large scale resources is required. Businesses do not want to invest & concentrate on managing these computing issues rather than their core business. Thus, they move to service providers. Service providers such as data centers serve their clients by sharing resources for computing, storage etc. and maintaining all those. To make optimal or maximum utilization of available resources, service providers (data centers) use one of emerging technology called, Cloud Computing.