All the flavors of cloud computing
Information Week had a great article in the November 9 issue on the definition as cloud. As the hot buzzword of the moment (replacing Web 2.0) I've heard many definitions but none as good as the ones provided below.
SOFTWARE AS A SERVICE
Salesforce automation was one of the first areas where delivering enterprise software online gained traction, led by Salesforce.com, which now has more than $1 billion in annual revenue. It replaces up-front licensing costs with monthly subscriptions, plus it often means easier deployment, maintenance, and upgrades, since employees just log on to a Web site to get access to applications. SaaS has spread to most application categories, and it’s the business model of choice for software startups.
INFRASTRUCTURE AS A SERVICE
This involves buying online server capacity as needed from vendors such as Amazon, IBM, Microsoft, Rackspace, Savvis, and Verizon. Customers pay for computing power based on consumption, much like electricity. The virtualized servers are typically offered in varying configurations, letting users choose processor,memory, operating system, and more.
STORAGE AS A SERVICE
This has the same pay-for-use business model as infrastructure. With data volumes soaring, storage-as-a-servic vendors such as Carbonite, EMC, IBM, Seagate, and Symantec say they can lower costs by taking on storagemanagement and insulate customers from the capital costs associated with hardware upgrades.
PLATFORM AS A SERVICE
Developers looking for a convenient way to build and deploy Web applications are increasingly using PaaS to do it. Available from Google, Microsoft, and others,these cloud services come with a development environment,and they make testing and deployment easier and more reliable.Vendors sometimes bundle infrastructure services with PaaS or link to infrastructure providers.
HYBRID CLOUDS
The hybrid cloud model tries to mesh the conventional on-premises data center model with the variable capacity that these cloud models offer. A company might buy on-demand computing capacity to handle Web traffic spikes from a majorpromotion or for a demanding research effort. Rather than buy hardware that runs far below capacity most of the time, the hybrid approach promises to let companies run their own servers at higher utilization,buying overflow capacity on demand. So far, it’s more concept than reality. Companies are building cloud infrastructures inside their own data centers, using virtualization and load balancing to gain higher utilization. But virtualization vendors make it hard to seamlessly switch those loads to outsiders. Vendors such as VMware and Citrix, as well as systems management vendors, are promising to tackle that problem and make hybrid a more practical option.
