Cloud Formations

Ready to try out the cloud? Here are three options:

1. Software as a Service (SaaS): Often geared toward the end user who needs access through a web browser or other thin client interface, SaaS provides access to applications hosted on a service provider's cloud infrastructure.

An organization can find just about any general office application available via the SaaS model. Customer relationship management, calendaring, e-mail and human resources management are among some of the more common applications delivered as services from the cloud infrastructure.

For IT departments, IT service management, spam filtering, intrusion prevention and other traditional security software are among the application types increasingly available via the SaaS model.

With SaaS, the user organization neither owns the application nor the associated servers, operating systems, storage, network or other IT resources required for its support and delivery. The applications essentially come as-is, with little to no opportunity to tweak user preferences.

Pro: Little to no infrastructure or staff resources required
Con: Not customizable

2. Platform as a Service (PaaS): Derived from the SaaS model, PaaS caters to developers' needs. Rather than simply delivering prepackaged applications via the cloud infrastructure, as is the case with SaaS, a PaaS provider offers up the entire computing platform and solutions stack needed for an application.

With PaaS, organizations can deploy acquired or custom applications without incurring the associated upfront provisioning and ongoing maintenance and management costs of the underlying infrastructure. The user organization has application control, the caveat often being that the developers must be comfortable with the PaaS provider's choices for programming languages, interfaces, development tools, database support and the like.

Pro: Can customize applications
Con: Must use the PaaS provider's programming languages, tools and other resources

3. Infrastructure as a Service (IaaS): This service model enables user organizations to forgo deployment of new data center equipment to handle growing operational needs. Rather, an organization obtains needed IT infrastructure from a cloud services provider, often via a self-service catalog.

While a user organization can run applications, databases, operating systems and other software on top of its selected infrastructure, it has no direct control over or access to those machines. The cloud services provider manages the infrastructure, including any scaling up or down as needed.

Infrastructure as a Service is similar in concept to a traditional dedicated hosting service, with two major differences: Organizations tap into a shared, highly scalable pool of resources, and they pay for only what's used on a utility basis. In other words, organizations neither have to preorder nor pay for dedicated gear sitting in an outsourced data center.

Pro: Limitless infrastructure at the ready
Con: Must share virtual infrastructure with other customers

Apr 01 2011