Everyone is talking about “The Cloud” which is a pool of shared computer resources. There are various types of Cloud depending on either the location of the infrastructure provided or on the type of services provided. There are advantages and disadvantages in each type.
TYPE I: Based on the location of Cloud’s infrastructure
Public Cloud: This is the most common type of Cloud used. The end user does not have any idea about the location of the cloud’s infrastructure. The Cloud is shared by users or companies spread across the globe. This is least expensive though there are security concerns.
Private Cloud: The cloud is located at the users’ premises and cannot be accessed by other companies or users. This is used less due to the cost, but is preferred by those who have a need for high security.
Hybrid Cloud: Some companies use both private and public clouds. They host critical applications on private cloud and non-critical ones on public cloud. Some companies use public clouds only to manage high loads.
Community Cloud: This is not so common. It is used by a group of companies. For example, companies within the same city or companies of same industry sharing a cloud.
TYPE II: Based on the services offered on the Cloud
SAAS: (Software as a Service) This is the most common form of service that is used over the Cloud. Various companies offer software which is hosted over the cloud. The end user accesses the software and pays as per use. For example, Salesforce.com, hubVirt’s products.
IAAS: (Infrastructure as a Service) The infrastructure or hardware is provided by the Cloud and the rest is managed by the users. This service is used by companies or individuals who do not want to get into maintaining data storage and servers. Users need to manage the software and applications by themselves. For example, Amazon EC2.
PAAS: (Platform as a Service) Computing platform is offered as a service over the Cloud. Life cycle of building and deploying an application is facilitated and supported over the platform. The underlying hardware and software are managed by the Cloud. Users need to develop and manage their applications. For example, Google App Engine, MS Azure.