Cloud computing represents a radical change in the way that organisations use and pay for Data Centre. Instead of hosting applications and data on an individual desktop computer, everything is hosted in the “cloud” – a collection of computers and servers accessed via the internet or a private network.
Cloud-based technologies have enabled a vibrant marketplace of software solutions, many based on open standards; these have changed the Data Centre landscape from one of the bespoke online systems to one including many interoperable commodity solutions too. In turn, this engenders changes in behaviour throughout organisations – rather than commissioning bespoke systems, organisations now often have the choice to deploy a best-fit one, off the shelf at a fraction of the cost. Resources such as computing power, storage, applications and services are used only when needed and paid for only when used.
The US National Institute of Standards and Technology‟s (NIST) definition of cloud computing is the most widely adopted one, and has been adopted for G-Cloud; it states that: “Cloud computing is a model for enabling convenient, on-demand network access to a shared pool of configurable computing resources (e.g. networks, servers, storage, applications, and services) that can be rapidly provisioned and released with minimal management effort or cloud provider interaction.”
Cloud deployment in the data centre
Cloud computing can be deployed in Data Centre through primarily four different models – private, public, hybrid and community. The primary differences between these models are in scope and access. For private cloud the infrastructure is managed and operated solely by an organisation; for public cloud the infrastructure is owned by a cloud provider and accessible to the general public or a large industry group; for hybrid cloud some resources are managed in-house and others are provided externally; and for community cloud the infrastructure is most likely shared and managed by several organisations.