Virtualization

Virtualization is the term which may be used in various cases like hardware, memory management, storage, desktop, data and network. In these cases it has different functions and meanings.
Here are some cases of virtualization:
Hardware virtualization - Execution of software in an environment separated from the underlying hardware resources

Memory virtualization -  Aggregating RAM resources from networked systems into a single memory pool

There are other cases as well - network virtualization, storage virtualization and many more.

Definition
Virtualization is a framework or methodology of dividing the resources of a computer into multiple execution environments, by applying one or more concepts or technologies such as hardware and software partitioning, time-sharing, partial or complete machine simulation, emulation, quality of service, and many others.

Note that this definition is rather loose, and includes concepts such as quality of service, which, even though being a separate field of study, is often used alongside virtualization. Often, such technologies come together in intricate ways to form interesting systems, one of whose properties is virtualization. In other words, the concept of virtualization is related to, or more appropriately synergistic with various paradigms. Consider the multi-programming paradigm: applications on modern systems run within a virtual machine model of some kind.

Generally speaking virtualization abstracts out things.

Benefits of virtualization

1. Adaptability is becoming an increasing focus for the management of modern business. With new opportunities and threats always lurking on the horizon, businesses must be able to quickly, efficiently, and effectively react to their dynamic environment. With regard to IT infrastructure, virtualization is perhaps the most effective tool for facilitating this adaptability. In virtualized systems, the expansion and reduction of technical resources can be performed seamlessly. Because physical devices and applications are logically represented in a virtual environment, administrators can manipulate them with more flexibility and reduced detrimental effects than in the physical environment. Through the use of virtualization tools (which vary from 1 case to another), server workloads can be dynamically provisioned to servers, storage device usage can be manipulated, and should a problem occur, administrators can easily perform a rollback to working configurations. Generally, the addition (or removal) of hardware can be easily managed with virtualization tools.
   Increased demand for data or database capabilities can be easily met with data and database virtualization through the management of new DBMSs or physical infrastructure with virtualization tools. So this is storage virtualization. All of these examples illustrate the adaptable nature of the virtual enterprise.
   
   
2. In addition to adaptability, there are lower operating costs through implementing virtualization within his or her infrastructure. There is much inherent efficiency that comes with implementing this type of system, because much of its focus is on optimizing the use of resources, thus reducing overhead for maintenance. Any element of current infrastructure can be leveraged more fully with virtualization. Switching costs for new operating systems or applications are lowered with the ability to more flexibly install and implement them. The consolidation of servers and storage space obviously increases the return on investment for this hardware by maximizing efficiency.
   
   
3. Lowering costs will allow organization to reallocate the IT budget towards initiatives that are not related to the maintenance of current systems, such as research and development, partnerships, and the alignment of IT with business strategy.
   
   
4. IT managers will be able to increase the productivity of employees across the entire organization through a properly implemented virtualization system. For businesses that rely on in-house application development, an increase in productivity and increased ease of implementation can be seen. Developers within a platform-virtualized environment can program in languages they are most proficient with. Debugging and testing applications becomes second nature with the ability to create contained virtual environments. In this instance, application and systems testing can be performed on a single workstation that employs a variety of virtual machines without the need to transfer and debug code to external computers. Enterprise-wide testing can be performed in isolated virtual machines, which do not interact with or compromise the resources actually being used on the network. Users in a virtualized environment do not know or care how their use of IT resources is being optimized. They are able to access needed information and perform work effectively and simply, without regard to the complexities that exist behind the scenes.
   

Risks
With any benefit, there is always associated risk. This is also the case for the practice of virtualization.
Following are the risk involved with virtualization:

1. The first problem that IT managers must be aware of occurs in the planning and implementation of virtualization. The organization must decide if, in fact, virtualization is right for their organization. The short-term costs of an ambitious virtualization project can be expensive, with the need for new infrastructure and configuration of current hardware. In businesses where cost reduction and flexibility of IT are not currently in alignment with the businesses strategy, other initiatives will be better suited. That is not to say that virtualization is not right for every environment, because most any organization can reap the benefits of a properly planned virtualization initiative. It is the timing and scope of such initiatives that must be scrutinized.
   
2. Another risk associated with virtualization can occur in businesses that do not have an efficient element of redundancy in their systems. Because the convergence of resources often takes place in virtualization environments, especially in that of server virtualization, the physical failure of one piece of hardware will impact all virtual elements that it manages. It is therefore necessary to ensure that backup systems are in place to deal with such problems. Fortunately, because of the isolation inherent in virtualized systems, backup processes can be greatly simplified.
   
3. A final problem that can occur in virtualized systems is increased overhead. The software layers inserted in between resources can chew up processor cycles, sometimes up to double-digit percentages.

Conclusion
With the positives far outweighing the negatives, virtualization is a technology that will soon be a universal practice. In the coming time, virtualization will become just a standard layer of the infrastructure stack. As costs for virtualization technology begin to decline, and more hardware manufacturers such as Intel and AMD begin to include built-in virtualization functionality in their products, it will become increasingly difficult to justify not using virtualization in an IT system. The unmatched effectiveness of virtualization to provide adaptability and reduce costs for the enterprise will empower IT managers and position their organizations for growth. Because of the inevitable induction of virtualization technology into the standard architecture stack, organizations from all types of businesses should begin sketching the path to their future in virtualization.