What is the Difference between a Public Cloud and a Private Cloud?

If you are considering a cloud solution for your company or other organization, you may have questions about whether you should create a private, public, or hybrid cloud. For that matter, you may be asking what the real difference is between these options.

As you probably already know, cloud services enable enterprises to share resources across the Internet or an intranet in a way that can often dramatically reduce infrastructure costs and planning. Large numbers of resources can be connected via networks (either private or public) to provide scalable infrastructure for data and file storage, application development and deployment, and many other functions. With these functions in mind, you will want to understand the fundamentals of each type of cloud solution in order to decide which system is appropriate for your needs.

Public Clouds

Owned and operated by third-party service providers, public clouds grant the benefits of affordability and ease of operation. Public clouds give users the benefit of pricing and available options based on the economy of scale: because they are large companies with many customers, the price for the cloud infrastructure, maintenance, and services are spread among many customers. These scale issues also allow users to enjoy on-demand scalability, so pricing often floats based on monthly usage.

On the other hand, public clouds tend to be more obvious targets for hackers. Data in these public clouds often lives on shared servers hosting cloud data for other users. A third-party is entirely responsible for monitoring, securing, and repairing issues with the cloud servers, as well. Still, for ease of deployment and operation, cost, and range of available options, public clouds are hard to beat.

Private Clouds

If you wish to keep things in-house, you can build a private cloud. The private cloud lives on your own servers and will be built entirely for the benefit of your enterprise. This allows you to build a cloud exactly meeting your company’s needs, providing superior privacy and security—providing your IT department remains vigilant—and greater overall control of your data.

Generally, there are two variations of private clouds. In an on-premises private cloud (or "internal cloud") the service is hosted within your own data center, which provides a custom level of protection. On the other hand, on-premises private clouds are often limited in size and scalability due to the expense. They often have higher operating costs, as well. On-premises private clouds are best for situations in which you need to retain complete control over your data and the configuration of your infrastructure and security.

Externally-hosted private clouds are hosted by an external cloud computing provider. The service provider sets up a dedicated and exclusive cloud environment with full guarantees of privacy. This allows you to have something approaching the privacy and security of an on-premises private cloud, but without the upfront cost or ongoing operating expenses of maintaining that cloud in your own facilities.

Hybrid Clouds

A third option is the hybrid cloud. Hybrid clouds combine the advantages of both public and private clouds by allowing a company to leverage the services of third-party cloud providers in either a full or partial manner. This increases the flexibility and range of options open to you for configuration, security, privacy, and scalability. The biggest advantage of a hybrid cloud is its ability to help you cope with unexpected surges in workload by sharing traffic between the unscalable in-house cloud and the off-site and highly scalable ones.