Your servers are what hold your organisations most valuable information.  From a high level overview, a server is hardware (the actual computer) and software that is loaded on a computer to make resources available for network users.

Virtualisation of the server platform allows us to take fullest advantage of our most expensive resources on a computer network.

Pre-virtualisation it was best practise to have a physical server per operation.  As an example it was common on a business network to have a Email server, File store Server and an accounting application server installed.  The rational behind this was to ensure that the different operations would not conflict or interfere with each other and ensure the most reliable and responsive operation from the servers.

The down side of this is two fold;

• On some sites we would require a large amount of servers (very expensive)

• If a physical server fails, unless you have a spare server EXACTLY the same, it is a very lengthy procedure to restore services.

Virtualisation allows you to have a physical computer and install multiple LOGICAL servers. This obviously means a far more effective use of the purchased resources.  Also because the actual servers are Logical, they all use the same hardware drivers.  This means you can transfer a logical server between hardware platforms simply.

Further to this, a well configured Virtual server environment will not only automatically transfer a logical server should the computer actually fail, but also offer "Load Balancing", dynamically shifting logical servers around your network to ensure best use of your computer investment.