Cloud Overview

Wikipedia defines Cloud computing as ‘describing a new supplement, consumption, and delivery model for IT services based on the Internet, and it typically involves over-the-Internet provision of dynamically scalable and often virtualized resources. This frequently takes the form of web-based tools or applications that users can access and use through a web browser as if it were a program installed locally on their own computer.'

Nexaweb views cloud computing as a continuum of leverage, opportunity and benefit.

 
On one end of the spectrum are private clouds enabled by virtualization technologies such as VMware and Xen. Many organizations are opting for this approach to simply move applications to a more efficient IT infrastructure. Private clouds dynamically provision computing resources on demand (by utilizing idle CPUs in the data center) to handle peak usage or to guarantee continuity of service in the case of server failures.

The next step is public cloud – enabled by vendors such as Rackspace and Amazon, all of which offer solutions that leverage their back-office infrastructure for storage and run-time.  Dedicated or shared CPU and storage resources are hosted, operated and secured remotely. They are provisioned on-demand for a monthly usage fee that depends on the type of hardware provisioned and the usage level (e.g., bandwidth or CPU consumption). Companies utilizing public clouds give up some control and flexibility (since they do not control the computing resources directly), but gain economic and speed advantages by not having to incur additional in-house data center overhead.

At the other end of the spectrum are platform as a service (PaaS) -- custom APIs and built-in libraries for quickly building custom applications running on a public cloud infrastructure -- and finally, software as a service (SaaS), offering turn-key Web-based applications on demand.