A common analogy to describe cloud computing is renting versus buying. Essentially, you rent capacity (server space or access to software) from a cloud service provider, and connect over the internet. Instead of buying your own IT requirements, you are renting from a service provider, paying for only the resources you use.
Cloud computing has 4 models in terms of different access and security options. Before you move your data into the cloud, you will need to consider which model works best for your business and data needs.
A private cloud is where the services and infrastructure are maintained and managed by you or a third party. This option reduces the potential security and control risks, and will suit you if your data and applications are a core part of your business and you need a higher degree of security or have sensitive data requirements.
A community cloud exists where several organisations share access to a private cloud, with similar security considerations. For example, a series of franchises have their own public clouds, but they are hosted remotely in a private environment.
A public cloud is where the services are stored off-site and accessed over the internet. The storage is managed by an external organisation such as Google or Microsoft. This service offers the greatest level of flexibility and cost saving; however, it is more vulnerable than private clouds.
A hybrid cloud model takes advantages of both public and private cloud services. By spreading your options across different cloud models, you gain the benefits of each model.
For example, you could use a public cloud for your emails to save on large storage costs, while keeping your highly sensitive data safe and secure behind your firewall in a private cloud.