Public Clouds

A public cloud is one in which the services and infrastructure are provided off-site over the Internet. These clouds offer the greatest level of efficiency in shared resources; however, they are also more vulnerable than private clouds. A public cloud is the obvious choice when

• Your standardized workload for applications is used by lots of people, such as e-mail.
• You need to test and develop application code.
• You have SaaS (Software as a Service) applications from a vendor who has a well-implemented security strategy.
• You need incremental capacity (the ability to add computer capacity for peak times).
• You’re doing collaboration projects.
• You’re doing an ad-hoc software development project using a Platform as a Service (PaaS) offering cloud.

Many IT department executives are concerned about public cloud security and reliability. Take extra time to ensure that you have security and governance issues well planned, or the short-term cost savings could turn into a long-term nightmare.

Private Clouds

A private cloud is one in which the services and infrastructure are maintained on a private network. These clouds offer the greatest level of security and control, but they require the company to still purchase and maintain all the software and infrastructure, which reduces the cost savings. A private cloud is the obvious choice when

• Your business is your data and your applications. Therefore, control and security are paramount.
• Your business is part of an industry that must conform to strict security and data privacy issues.
• Your company is large enough to run a next generation cloud data center efficiently and effectively on its own.

To complicate things, the lines between private and public clouds are blurring. For example, some public cloud companies are now offering private versions of their public clouds. Some companies that only offered private cloud technologies are now offering public versions of those same capabilities.

Hybrid Clouds

A hybrid cloud includes a variety of public and private options with multiple providers. By spreading things out over a hybrid cloud, you keep each aspect at your business in the most efficient environment possible. The downside is that you have to keep track of multiple different security platforms and ensure that all aspects of your business can communicate with each other. Here are a couple of situations where a hybrid environment is best.

• Your company wants to use a SaaS application but is concerned about security. Your SaaS vendor can create a private cloud just for your company inside their firewall. They provide you with a virtual private network (VPN) for additional security.
• Your company offers services that are tailored for different vertical markets. You can use a public cloud to interact with the clients but keep their data secured within a private cloud.

The management requirements of cloud computing become much more complex when you need to manage private, public, and traditional data centers all together. You’ll need to add capabilities for federating these environments.

Re-blogged From: Judith Hurwitz, Robin Bloor, Marcia Kaufman, and Fern Halper | Cloud Computing For Dummies