Virtualization is a way to run several independent virtual operating systems on a single physical computer. It is a way of maximizing physical resources and, in turn, maximizing the investment in hardware.

Application virtualization, also called application service virtualization, is a term under the larger umbrella of virtualization. It refers to running an application on a thin client; a terminal or a network workstation with few resident programs and accessing most programs residing on a connected server. The thin client runs in an environment separate from, sometimes referred to as being encapsulated from, the operating system where the application is located.
Application virtualization fools the computer into working as if the application is running on the local machine, while in fact it is running on a virtual machine (such as a server) in another location, using its operating system (OS), and being accessed by the local machine. Incompatibility problems with the local machine’s OS, or even bugs or poor quality code in the application, may be overcome by running virtual applications.

Typical enterprise data centers contain a huge number of servers. Many of these servers sit idle as the workload is distributed to only some of the servers on the network. This results in a waste of expensive hardware resources, power, maintenance and cooling requirements. Server virtualization attempts to increase resource utilization by partitioning physical servers into several multiple virtual servers, each running its own operating system and applications. Server virtualization makes each virtual server look and act like a physical server, multiplying the capacity of every single physical machine.
The concept of server virtualization is widely applied in IT infrastructure as a way of minimizing costs by increasing the utilization of existing resources. Virtualizing servers is often a good solution for small- to medium-scale applications. This technology is widely used for providing cost-effective web hosting services.

Running A Website

This is the most obvious and popular use. Since virtual private servers provide more resources for your website (e.g. CPU, RAM, etc.) than shared hosting, you’ll find that your website feels more responsive. Plus, with full control over the virtual server, you can install and remove software at will according to your needs rather than being stuck with what the host offers.

Hosting A Server

Have you ever wanted to run your own Minecraft server? Or maybe you need a private Mumble host for your friends to chat on? Or if you’re leaning more towards business uses, you could use a VPS for hosting files and other media. Basically, anything that runs as a server can be run on a VPS.

Testing New Environments

Since dedicated hosting is so expensive, virtual servers can be used as testing grounds for server setups that aren’t ready for live deployment. They can also be useful for quick exploration and testing of new components: operating systems, frameworks, software, etc.

Seeding Torrents

Also known as a seedbox, you can use a virtual server strictly for torrenting purposes. If you torrent frequently, moving all of that action to a remote VPS not only frees up a lot of home bandwidth, but it also allows you to keep it going 24/7.

Private Backups

The leftover disk space in a VPS plan can be used to store private backups of important files. It’s cheaper to use cloud-based storage from a price-per-gigabyte perspective, but if you’re already using a VPS for some other reason and you have leftover space, you might as well think of it as free file storage.

Without a doubt, the greatest advantage of server virtualization is cost. In addition to energy savings and lower capital expenses due to more efficient use of your hardware resources, you get high availability of resources, better management, and improved disaster-recovery processes with a virtual infrastructure. You save on physical space, reduce power consumption and the need for cooling, and are able to rapidly deploy a new application without ordering new hardware.
As for cons, if the virtualized server were to go offline, every site that the server is hosting would also fail. Most enterprises use a cluster or some other technique to prevent such outages. Also, security has not yet been perfected.
Hardware is going to fail; that’s the nature of the beast. But virtualization means that instead of losing a day’s worth of work, Trinity’s tech staff can be proactive instead of reactive. “All in all, it’s a great stress reliever and time-management tool”.