International Journal of Advanced Research in Computer Science and Software Engineering (IJARCSSE)
Cloud computing creates a virtual model for sharing of files and services over a scalable network of nodes. It has been appreciated as the next logical step after grid computing on the way to utility computing, where computing resources are obtained as subscription based service just like water and electricity. From business viewpoint, it is seen as an economical model for leasing technical resources. As cloud computing make available an on-demand, pay-as-you-go computing resources. Service Level Agreement (SLA) between customer and provider becomes a key aspect.