Once upon a time, email was something you could only send and receive using a mail client. But then Web-based services such as Hotmail, Gmail came along and carried email off into the cloud. The email programme is running on the server and all your emails including the software is stored on the cloud, easily accessible from a Web browser, wherever we happen to be.
If you are using Gmail, Youtube, Facebook, Hotmail, Twitter, Flickr, etc. believe it or not you’ve been using Cloud for long times.
Although users don’t need to have knowledge of, expertise in, or control over the technology infrastructure in the “cloud” that supports them, a conceptual understanding would be useful.
“Cloud Computing,” in simple words, means “Internet Computing.” With Cloud Computing users can access database resources via the Internet from anywhere, for as long as they need, without worrying about any maintenance or management of actual resources. Besides, databases in cloud are very dynamic and scalable.
The cloud computing system can be conceptually divided into two sections: the front end and the back end, which connect to each other through a network, usually the Internet. The front end or user interface could be any device such as a desktop, laptop, mobile devices, smart phone, PDA, etc. and this could be located anywhere. The back end is the “cloud” section of the system which is the collection of servers connected on a public/private network. For instance, we use web browsers such as Firefox, Chrome, Internet Explorer, etc. to access email services.
Deployment Models of Cloud Computing
- Public Cloud
- Private Cloud
- Hybrid Cloud
A public cloud is one based on the standard cloud computing model, in which a service provider makes resources, such as applications and storage, available to the general public over the Internet. Public cloud services may be free or offered on a pay-per-usage model. It is easy and inexpensive set-up because hardware, application and bandwidth costs are covered by the provider.
Private clouds are built for the exclusive use of one client, providing the utmost control over data, security, and quality of service. The company owns the infrastructure and has control over how applications are deployed on it. Private clouds may be deployed in an enterprise data centre, and they also may be deployed at a co-location facility.
Hybrid clouds combine both public and private cloud models. They can help to provide on-demand, externally provisioned scale. The ability to augment a private cloud with the resources of a public cloud can be used to maintain service levels in the face of rapid workload fluctuations. A hybrid cloud also can be used to handle planned workload spikes.
Types of Cloud Computing
- Software as a service (SaaS) features a complete application offered as a service on demand. A single instance of the software runs on the cloud and services multiple end users or client organizations. It is a software distribution model in which applications are hosted by a vendor or service provider and made available to customers over a network, typically the Internet. ERP, CRM, Google Docs are examples of SaaS.
- Platform as a service (PaaS) is a way to rent hardware, operating systems, storage and network capacity over the Internet. The service delivery model allows the customer to rent virtualized servers and associated services for running existing applications or developing and testing new ones. Windows Azure is a common example of PaaS.
- Infrastructure as a service (IaaS) delivers basic storage and compute capabilities as standardized services over the network. Servers, storagesystems, switches, routers, and other systems are pooled and made available to handle workloads that range from application components to high-performance computing applications. Amazon Web services is a basic example of IaaS.
Benefits of Cloud Computing
- Reduced Cost – Cloud technology is paid incrementally, saving organizations money.
- Increased Storage – Organizations can store more data than on private computer systems.
- Highly Automated – No longer do IT personnel need to worry about keeping software up to date.
- Flexibility – Cloud computing offers much more flexibility than past computing methods.
- More Mobility – Employees can access information wherever they are, rather than having to remain at their desks.
- Allows IT to Shift Focus – No longer having to worry about constant server updates and other computing issues, government organizations will be free to concentrate on innovation.
Issues in Cloud Computing
- Security – Cloud hosting is simply not the most secure environment at present. If you’re looking to achieve and maintain data privacy requirements for PCI compliance, HIPAA compliance, SOX, E-commerce, and so on, then cloud hosting is not the solution for you.
- Redundancy – One of the misconceptions of cloud hosting is that it’s hosted “in the sky and not in a datacenter,” which is not true. Cloud hosting resides in a single datacenter. The site owners had a huge reality check and quickly learned of the single-points of failure within a cloud environment.