Disaster recovery: IaaS allows a business to quickly recreate the building blocks of an on-site system (servers, storage, networking) that has failed. By restoring the middleware, tools and application to a cloud-based system, the business can carry on functioning whilst they recover the in-house system. High Performance Computing (HPC): The pay-as-you-go nature of IaaS allows users to access very large amounts of compute power, without the need to purchase a physical HPC system. This is particularly useful for shorter term research or data mining projects, as well as proof-of-concept scenarios. Data storage and backup: IaaS allows a business to store multiple copies of data in the cloud, which by definition is ‘off-site’. The ability to quickly and easily scale the size of data stored, and configure how the data is protected and backed up, make IaaS an extremely flexible storage option.