The cloud isn’t a technology. It’s more of an approach to building IT services – an approach that harnesses the power of servers, as well as virtualization technologies that combine servers into large computing pools and divide single servers into multiple virtual machines. And there are several different deployment models for implementing cloud technology.
The four primary types of cloud models are:
Each has its advantages and disadvantages with significant implications for any organization researching or actively considering a cloud deployment.
A public cloud is a cloud computing model in which services, such as applications and storage, are available for general use over the Internet. Public cloud services may be offered on a pay-per-usage mode or other purchasing models. An example of a public cloud is IBM’s Blue Cloud.
A private cloud is a virtualized data center that operates within a firewall. Private clouds are highly virtualized, joined together by mass quantities of IT infrastructure into resource pools, and privately owned and managed.
A hybrid cloud is a mix of public and private clouds.
A community cloud is an infrastructure shared by several organizations which supports a specific community.