Microsoft's Hyper-V allows you to run multiple installations of an operating system as 'virtual machines' on one hardware device. The installations believe they are running on their own hardware. Running multiple servers on one physical server offers great cost advantages - but the benefits don't stop there because there's a wealth of other features included:
- Image-based backup - your backup isn't tied to the hardware, you can take an exact snapshot of your system quickly, regularly, and without disruption to users. An update goes wrong? The server fails? Simply roll back.
- Live migration - move your server from one physical server to another whilst it's on and serving users. This means no downtime.
- Replica and failover - have a copy of your servers on separate hardware, or at another site for disaster recovery. This ensures that should something fail, your business can be quickly back on its feet.
- Dynamic memory - Share your RAM between multiple servers, ensuring it's utilised where it is most needed.
What's more, it's all free. I know what you're thinking "but is it really free? And which bits? Does it count as one of my Windows Server licences?"
Hyper-V Server 2012 R2 is free - no time limits, no feature restrictions. You can download it here.
Seems straightforward, so where's the confusion?
Hyper-V Server 2012 R2 doesn't have a GUI (Graphical User Interface). The features are there and can be configured, however, the GUI is not. Instead, you can use Powershell, a command line based management tool.
You can add Hyper-V as a role to full Windows Server. I know what you're thinking here "but wouldn't that make it quite expensive, as you'd have to use one of your two licences, right?" Thankfully, no.
Windows Server licences - a recap
Windows Server 2012 R2 comes in two versions:
1. Standard - this allows you to run two virtual machines per processor. Each extra copy you buy allows two more virtual machines running Windows Server to be run on your server.
2. Datacenter - think of this as the 'all you can eat' option. As many virtual machines running Windows Server as your physical server can handle.
You can install a full copy of Windows Server 2012 R2 on your server without using up one of the two virtualisation licences, they are for your virtual machines.
So I get a free copy of Windows Server - do I get three altogether?
For Windows Server 2012 Standard:
Running Instances of the Server Software.
For each server that you have assigned the required number of software licenses you may run on the licensed server, at any one time:
- one instance of the server software in one physical operating system environment, and
- two instance of the server software in one virtual operating system environment
However, it is best practise to only have your underlying operating system running your virtual machines, with no other roles installed. Remember, if your OS installed on your physical hardware has issues this may affect your virtual machines. It may also dominate available resources.
Virtualisation is a fantastic tool for organisations looking to reduce the setup and running costs of a server. To find out how it can help your business (and let us worry about the licensing quirks!), simply give us a call.