What is virtualisation?

15 October 2010 |


Virtualisation involves the migration of systems from the physical to the virtual (P2V), moving them from the original physical hardware to virtual operating environments.

This allows businesses to make much more efficient use of expensive and bulky hardware and the information stored on it, offering them the opportunity to rationalise their data centres and servers. Operating system virtualisation is the most common form of virtualisation activity.

Is virtualisation a new idea?


“Virtualisation actually goes back to the 1970s, and was first put in place on IBM mainframes to allow end users to run multiple applications on the same server,” explains Steve Hughes, cloud and virtualisation specialist at network operator Colt.

The idea was initially formulated to tackle a very specific problem. Vendors of enterprise software applications used often to specify that their customers needed to run each of their applications on a separate server, on the basis that multiple software applications running on the same server can interfere with each other. These customers were consequently driven to build large and expensive data centres, where the utilisation of individual servers could be as low as 10% to 15%.

By creating self-contained representations of the underlying operating system, virtualisation allows applications to run independently of separate chunks of big iron.

“Virtualisation is like putting software applications in containers, so that you separate the application from the actual hardware,” says Hughes. “There are now a number of different types of virtualisation, but VMware started the process by developing something they called a hypervisor. This basically slipped between the hardware and the operating system so that you could run various self-contained applications on the same server, effectively stacking them up.” This, he says, consolidates resources and increases flexibility, allowing customers to rationalise their use of servers, running several different applications on the same machine without worrying about interference.

So what are its measurable advantages?


Some of the advantages of virtualisation are very clear. It can increase the utilisation rates of server capacity from 15% to closer to 80%, therefore significantly reducing the number of servers required by businesses. Companies previously running 100 legacy servers may find they need as few as 20 servers after consolidation. Obviously, this reduces capital and operational expenditure, allowing savings in hardware costs, system administration costs and the costs of data centre space. It also reduces the energy costs of running hardware and providing cooling, and by reducing energy requirements has the benefit of being environmentally friendly.

Virtualisation also allows businesses to optimise their data network, for which they are likely to be paying a service provider or systems integrator a lot of money. It also means they can support new business models on a secure infrastructure. It can lead to significant operational efficiencies, making it easier to maintain servers and install new software, shifting the focus from IT maintenance to one of IT innovation. As well as combining separate routers into one common infrastructure, virtualisation allows businesses to decouple their infrastructure and services into secure and isolated networks. This can, for example, allow businesses to separate services like accounting, billing and services for different divisions on the same equipment.

Virtualisation also has significant benefits for disaster recovery. As Hughes explains: “It means that everything in containers can be moved around data centres and different locations, which has a profound effect on automating the data industry. You can take a snapshot of a file and then replicate it somewhere else, which makes disaster recovery much easier.”

So what are the business models that virtualisation enables?


Virtualisation allows businesses to move applications more readily between their own data centre and that of a third party, like a service provider. A service provider’s data centre can then run a shared environment, which is in effect cloud computing, allowing a business to move an application from their site to the cloud site. Virtualisation is one of the key enabling technologies for cloud computing.

“The use of virtualisation technology has grown exponentially over the past decade,” explains Zeus Kerravala, senior vice president with consulting firm Yankee Group. “However, its primary use has been to consolidate the number of servers in corporate data centres. Recently though, advancements in virtualisation technology have given rise to the next wave of usage for this technology. That is using virtualisation, and cloud computing, to separate all of the components of computing, not just servers, to simplify and make computing more efficient. This will work by creating various pools of computer resources that are mobilised and move around the network as business policy dictates.”

What does this mean for the service provider?  


Pressure is now on the network service provider that operates the connection between hosted application and user to do what wasn’t possible before – to be able to scale up processing capacity to meet surges in customer demand, brought about for example by seasonal variations on the volume of business they are doing, then scale down in quieter times.