How to Choose a Cloud Hosting Service

PC World - Not sure what cloud computing is, or how it can benefit your business? In this article, I'll introduce you to the cloud, help you interpret the buzzwords, and explain how your business might save time and money using a cloud hosting service such as Windows Azure, Amazon EC2, or Rackspace.

Discovering the Cloud and Cloud Computing

People use "cloud" as a buzzword when describing either the Internet or an intranet in association with some type of service or application offering. When you hear the term "public cloud," think of the Internet; when you hear "private cloud," think of your company's intranet. Usually, "cloud" by itself refers to the public cloud.

The phrase "cloud computing" refers to Internet or intranet applications and services that you typically access, run, or manage via a Web browser. Such services often don't require you to install software on your computer.

Here's another way to look at it: Cloud computing is the delivery of computing as a service rather than as a product. Instead of purchasing, installing, and running a program on your local computers, the program runs on the provider's computers, and you pay a monthly or yearly fee for access.

You can find three main types of cloud computing service providers.

• Software as a Service (SaaS) providers, such as Google Docs, Microsoft Office 365, and Salesforce, are services designed for end users. As such, they represent the end result of cloud computing.

• Platform as a Service (PaaS) offerings, such as Windows Azure, are services that IT personnel use in application development and for providing applications (SaaS) and Web hosting to end users. Basically, your IT staff gets remote access to virtual computers hosted at the provider's data centers. PaaS providers typically offer a managed Windows or Linux operating system, which means that your business can dedicate more resources to development and fewer to configuring and maintaining the OS. The trade-off is that your IT personnel will have less control over the underlying OS.

• Infrastructure as a Service (IaaS) providers, such as Amazon EC2 and Rackspace Cloud Hosting, are similar to PaaS providers, but they usually offer your IT personnel more control over the OS. Although they typically don't provide automatic OS updates, your business can use the raw infrastructure to develop and deploy applications on pretty much any platform or OS.

PaaS and IaaS Providers

I'll focus on PaaS and IaaS providers here. If you're familiar with the concept of virtual computing, you might think of these services as providing virtual machines (like VMware or VirtualBox) via the Internet.

PaaS and IaaS providers supply access to their shared data centers, giving you the reliability, redundancy, and security of a global enterprise data center network. This saves you time and money, because you don't need to purchase and set up servers from scratch, and you pay only for the resources you consume. These services are particularly cost-effective for short-term projects, but they also deliver scalable, on-demand resources. For instance, within minutes you can double the amount of memory that your website might need to respond to a surge of end users.