What is the virtual machine/virtual server, and why has this issue became such a needed and common solution for organizations?
The virtual machine provides a tool that can run different applications, operating systems on the same machine as if it was a physical computer. The idea is that you can install either a full VMware server (virtual server), that is designated to run different operating systems simultaneously. This means you can install several servers on one hardware machine, and they all will work fine as if they were all different physical servers.
This shows that on one hardware physical computer, we can run different servers and services, and save the cost of buying other hardware machines. This solution enables many different advantages which are not just cost-effective but more flexible and for different purposes that benefit organizations.
Virtual services for QA purposes: Usually QA (Quality assurance) department, needs to simulate a certain environment to enable the testing as close to the real environment where the application/device will be running. When you know a client has a specific network environment, or a specific server that he needs our application to run upon, we will need to do testing of our development on that environment.
The simplicity of it all is that without buying a specific hardware, installing the environment of the client on that hardware and then do out testing. We can just install the environment on a virtual server, do our testing, play around with it (since it is a server (we installed) for the testing purposes and it is not a real server that serves others) and when we are done, we can shutdown this environment we built, and clear the space for our next QA project.
Virtual servers for support: When we need to give a client support, and we stumble upon a situation where we can’t reach a solution since the client is using an environment that we do not have on our system and we want to simulate exactly the environment the client has, so we could see the same problems he encounters. We can build such an environment easy, simply by creating the virtual system the client uses, install all of the applications he is using, and then our system, to test and see what he stumble upon, and find a solution locally on our system.
Again when we are done, we can just remove that server, and clear space for a new server to be installed. This is the flexibility the virtual environment enables us to use.
Virtual servers for multiple organization services: The virtual server can run multiple servers at the same time on the same machine. There are servers 
organization uses, that do not need many resources to run, like a monitoring server, or a DNS server, or a DHCP server, etc…
Those servers, without the virtual environment, will have to be installed separately on different hardware machine, so for each of the server I mentioned Monitoring server, DNS and DHCP servers, we will be keeping 3 different hardware computers, and on each one, we will install a different server.
You can understand that we are keeping 3 hardware servers, for applications that probably will not even use all of the hardware PC/Server resources it will be installed on, and we will be wasting valuable resources, and of course, it occupies more space on our server room (3 servers take more space than one).
Virtual servers enable us to reduce cost, be more efficient, configure the exact resources and image requires for proper function and be more efficient by maximizing the use of one hardware server, with multiple solutions on one machine.
Virtual server as a reliable backup system: When we install instances/images (each instance represents a different server on a virtual machine), we can define a schedule that will save the instance snapshot or a full exported file of the whole instance.
This enables to restore into a previous snapshot, in case we caused damage to the server, or restore the image fully, in case it is malfunctioning and we can’t use it anymore, so we restore from the last exported image (which is a stored file of the whole operating system with everything on it), a process that can take around 30 minutes maybe less, depends on the size of the server and how much was installed. This saves the whole re-installation process from scratch, and re-deploy of all the necessary applications, and their configuration to make them run, as the original server
did.
Anyone who uses NORTON GHOST to keep a whole computer image backup knows how simple it makes the restore operating and of course saves time and the headache of needing to re-install re-configure everything from scratch.
These are the most important benefits of using a virtual server, and I would have to say that you will need at least one virtual server on an organization just to enable a flexible environment for IT to use, in case a quick server needs to be deployed for a very urgent project.