Cloud Computing Definition is that it is a shared pool of configurable computing resource (eg. networks, servers, storage, applications, and services) network on demand over the internet. Cloud computing literally, is the use of remote servers (usually accessible via the Internet) to process or store information. Access is usually using a Web browser. Save files on a server via the Internet is one example.
Public cloud: This type of infrastructure is accessible to a wide audience and belongs to aprovider of "cloud services."
Private cloud: The cloud infrastructure works for one organization. It can be managed by the company itself (internal Private Cloud). In the latter case, the infrastructure is dedicated to the company and accessible via secure VPN-type networks.
The Cloud Community:The infrastructure is shared by several organizations that have common interests (e.gsafety requirements, compliance ...). As private cloud, it can be managed by the organizations them selves or by third parties.
Hybrid cloud: Infrastructure consists of two or more clouds (private, Community or Public), which remain unique entities but are bound together by standardized or proprietary technology, enabling data portability or applications.
Cost Reduction: Cloud computing is seen as an incremental investment, companies can save money in the long term by obtaining resources.
Storage increase: instead of purchasing large amounts of storage before the need, organizations can increase storage incrementally, requesting additional disk space on the service provider when the need is recognized.
Resource pooling: in the IT industry, this feature is also known as Multi-tenancy, where many users / clients share a type and varied level of resources.
Highly automated: As the software and hardware requirements are hosted on a cloud provider, IT departments sites no longer have to worry about keeping the things-to-date and available.
Greater mobility: Once the information is stored in the cloud, access it is quite simple, just you have an Internet connection, regardless of where they are located.
Change the IT focus: Once the responsibility of the computing environment has,
essentially shifted to the cloud provider, IT departments can now focus more on the organization's needs and the development of strategic applications and tactics and not on operational needs of the day-to-day.
Towards Green IT: By releasing the physical space, virtualization of applications and servers contributes to the reduction of equipment as well as the need for air conditioning, consequently, less energy waste.
Keep updated things: Similar to change the IT focus, this benefit is because of the new demands of providers cloud services, ie, the focus of providers is to monitor and maintain the most recent tools and techniques for the contractor.
Quick elasticity: this characteristic has to do with the fundamental aspects of Cloud flexibility and elasticity. For example, the web shops carry a standard amount of transactions during the year, but it is necessary to increase near Christmas time. And of course these stores do not want to pay for that capacity at peak during the rest of the year.
Measurement service: which means services monitored, controlled and reported. This feature allows a model of pay-per-use service, or pay for use. It has similarities with the concept of telephone service packages where you pay a standard signature to basic levels, and paid extra for the additional service, without changing the contract.
The various problem areas for cloud computing environments are:
Security: As the data are no longer in their own organization, security becomes a major issue and questions must be answered, such as: Data is protected as adequate? There is a hacker-proof system? Can you meet the requirements regulations and government for privacy? How do you discover the leak information? Note also that corporate governance is always very concerned about the data that is stored outside the organization.
Location and Data Privacy: Where the data is stored? How data is stored? The provider has adequate security for data in places where they are stored?
Internet addiction: Since the cloud features are not available on the local network, you have to worry about the availability of the Internet. If you lose access to the Internet out, what that happens to your cloud computing environment? If your service provider increasing period unavailability, what you do with your employees and customers? What do you do in case of increased latency or delays the answers?
Levels of availability and service: Most organizations are familiar with the agreements service levels. The service level agreement specifies the amount of service capacity that someone has to provide, along with the penalties for not providing this level of service. How you can be sure that the cloud service provider has sufficient resources to maintain a service level agreement you signed with them?