Virtualization is one of the hottest topics in information technology for a very good reason; Virtualization literally separates the operation of your computer from the physical hardware without an impact on performance. This makes your virtual machine movable, scalable and easy of manage.
A virtual machine exists simply as data. Being data means is can be moved or replicated as easily as copying a file or files. Copy the virtual machine to another physical computer and it will run exactly the same way. For all intents and purposes, it will actually be the exact same machine, even if it’s running on dramatically different hardware.
If your physical server has a hardware failure, the virtual machine can run on different hardware. Your entire virtual machine can be backed-up, not just the files on it but the entire machine. Advanced virtualization solutions like VMware can even have two versions of the same server at two locations that appear to be the same server. One server can take over for the other, should it go down due to hardware failure.
One physical computer can run a multitude of virtual machines. A virtual machine can also be spread out across a multitude of physical servers. This dynamic means that one virtual machine can harness the power of multiple physical machines or physical computers can provide redundancy for virtual machines.
Adding more power for more virtual machines becomes as easy as adding new physical computers. This provides you with incredible flexibility in initial hardware purchases, maintenance and upgrades.
Ease of Management
Since one physical computer can handle multiple virtual machines, the machines can be created for dedicated tasks. The reason to do this is to take advantage of physical hardware while still dedicating each server to individual tasks. For example, rather than having a single server running Microsoft Exchange, file sharing and Active Directory you would have three virtual servers where each only hosts one service.
By isolating the virtual machine to a single task, it can be managed more effectively. Say, for example, an update to Microsoft Exchange causes it to crash. If every service were on one server, then they would all go down while you attempt to fix Microsoft Exchange. With dedicated virtual moachines, you would only need to take down the Microsoft Exchange virtual machine to repair it. The other servers continue to operate as normal.
Using an advanced virtualization solution like VMware, you can also take advantage of snapshotting, high availability, fault tolerance, and vMotion. Snapshotting allows you to save the current state of a server and return immediately to it; this gives you the ability to make changes without fear of rendering the server useless. High availability, fault tolerance, and vMotion allow you to run a virtual server across networks and hardware so that if a physical server goes down, the virtual server will continue to function.