What is Hyper-V and what's all the fuss about?

What is it?

Hyper-V is a virtualisation product.

Thanks for that but what is virtualisation?

Virtualisation is one of the THE buzzwords for the last couple of years or so. It has been sold as the solution to world poverty, war, famine, etc. It is, of course, none of these things. What virtualisation does is very simple. It allows a computer to run more than one operating system at once, essentially allowing a single physical computer to become multiple computers. Each of these new ‘computers’ are referred to as virtual computers or VIRTUAL MACHINES. Think of it as being like partitioning up a room for different, private, functions rather than having one great big open plan space to use where everybody can see and hear everybody else, whether they want to or not.

Sorry, can’t see the point. Why not just run more than one computer?

Because companies have concerns about a number of areas that virtualisation can help with, these areas include;

• POWER CONSUMPTION – There is SERIOUS pressure on companies to be more green and to get with the green agenda. This is a good thing and a definite opportunity for them.
• SPACE – Space in the server rack costs money over and above the purchase of the kit. If it is possible to run less physical kit and still achieve the same results then it will save space and therefore money over and above just the purchase of the kit.
• SERVER UTILISATION – Most servers don’t run at anything like the actual capacity that they can run at. Most are capable of doing far more than is asked of them. As a result there is a lot of wasted capacity sat in company server rooms.
• DISASTER RECOVERY – Each virtual machine is now just a set of files that exist on the host hardware. These can be backed up, moved, cloned and generally managed more easily in the event that there is a disaster.
• FLEXIBILITY – Rather than looking at a handful of servers in terms of the individual jobs that they do, they can be looked at as a pool of resources which can be used as required and which can take on different jobs as capacity requirements change through the working week, or even day if required.

Why not just put more applications onto a single server computer? Surely that’s the same thing?

Not really, as there are many reasons why applications shouldn’t be mixed under the same operating system. Traditionally a server has been bought as a device to run a single application such as Exchange or SQL Server. This has led to some of the capacity that is being wasted as these applications don’t play nicely together but don’t need all the processor and memory that are on offer. From a purchasing perspective it actually may not be possible to buy a ‘small enough’ server to equate to the load to the hardware.

Software like Exchange also often really doesn’t like having to co-habit with other software. It wants the computer all to itself, even if it doesn’t need all of it. Other software would, in very simple terms, ‘get in the way’.

Finally on this point, not everything runs on Windows so to have a mixed Windows/Linux environment has previously required dedicated hardware for the two operating systems. In a Windows 2008 / Hyper-V server partitions can be created for Windows Virtual Machines AND Linux virtual machines on the same host hardware.

What about VMware?  Isn't that the same?

Yes but no.  They are both virtualisation solutions but with some differences.  Which one is better?  Take a at my previous article Hyper-V vs. VMware

Posted by Adam White-Bower on Wed, 03/03/2010 - 2:43pm