$$ - An Introduction To Server Virtualisation

Virtually speaking

The word ‘virtualisation’ is thrown around as much in the IT media as the term ‘recession’ is dominating the mainstream news. Virtualisation is now becoming even more relevant, particularly to the medical industry, where any advantage in increased efficiency and reduced overheads is vital during this time of economic uncertainty.

As with any media hype, it can be difficult to cut through conflicting reports to get to the facts.

So what exactly is virtualisation? In basic terms it is a way to run multiple operating systems and servers on one computer. This is significant when, next to wages, information technology can represent quite a hefty slice of a company’s outgoings. Today’s present climate means the main benefit going virtual — maximising usage — makes it markedly more attractive, although it’s not entirely without its quirks.

The bottom line is that virtualisation is a reality any competitive organisation needs to face.

Virtual timeline

For those who assume that virtualisation is a relatively new frontier, think again. In reality, virtualisation has a long history in the IT world and is now a mature technology.

The concept has been around for almost 50 years and actual virtualisation techniques have existed for close to 45 years. It is gaining acceptance in the small server arena after enjoying a few years in mainframe markets. This is largely due to the capability of powerful contemporary hardware and its capacity to meet the increasing emphasis being placed on efficiency in the global marketplace.

Virtualisation in a nutshell

Virtualisation is the decoupling of physical server hardware (referred to as the Host hardware) from a single operating system.

Virtualisation allows a physical machine to operate many different operating systems simultaneously in isolation from each other (referred to as Guest operating systems). Each of these operating systems function the same way as a normal server and operating system do: They have their own allocation of resources on the physical computer such as memory (RAM), file space and networking components.

Server virtualisation is different from installing multiple applications on a single server. If you did this while running a single operating system, there would be many issues that would need to be taken into account. For example, it would be critical that the applications did not interfere with one another — some applications simply cannot run side-by-side. For example, it’s advisable to separate servers for Microsoft’s Exchange Email Server from file sharing tasks.

There are three popular approaches to server virtualisation: The virtual machine model; the paravirtual machine model, and the virtualisation at the operating system (OS) layer.

Of these, the virtual machine model is the version which has been most widely accepted in the marketplace. It uses the host/guest arrangement in its truest version, allowing the guest operating system to run without modifications, while maximising resource efficiency. VMWare, the clear market leader in virtualisation software, uses this model and it is the most established format for the small to medium business sectors.

The virtues of virtualisation

There are three main reasons why I use virtualisation at Jabbawoki: Space, time and money.

Some of the biggest drawcards of starting virtualisation in your company are the entry-level products that vendors offer for free. VMWare Server was my first introduction to virtualisation. It runs on Windows or Linux and can be installed in less than 10 minutes.

As a hosting company, we run numerous applications. Many are just there for testing purposes, where as some are for training, and there are about a dozen used to run our own business.

Many of these applications normally require two to three servers. If we followed the golden rule of IT “One application, one server”, we simply wouldn’t have enough space in the office and data centre to house the machines required.

After converting a few machines onto the VMWare Server platform, our server list grew but our hardware requirements shrunk. Deploying a server from scratch is a time-consuming process — the installation and basic setup time can easily stretch into three days. This doesn’t even include application specific setup. With virtualisation being used almost universally at our company, we now have ready-made templates specific to our setup requirements which significantly reduce our deployment time.

When is going virtual a good idea?

The basic impetus behind server virtualisation is that many servers are under-utilised. Today’s physical servers often include multiple processors, each containing multiple CPU cores. They also tend to offer large amounts of both memory and disk space.

While some servers need these types of resources, others do not. If you’re running a simple application, there is a good chance that the vast majority of a server’s capacity is not going to be utilised.

By opting for virtualisation, you can consolidate multiple systems into a single physical server. This means you can reduce the number of physical servers required by optimising the resources of the existing server.

How can virtualisation benefit my business?

There are a number of key reasons why virtualisation can be a winner for businesses. Firstly, server consolidation reduces the number of physical servers that need to be purchased, maintained and upgraded. Fewer servers mean a reduction in on-going costs for space and energy. Energy costs are represented in terms of running the infrastructure and controlling the environment (air temperature, humidity). The latter represents 20 to 40 per cent of the overall energy cost for computing infrastructure.

Secondly, virtualisation makes computing infrastructure more nimble when responding to business needs in shorter timeframes. Upgrading available resources such as RAM and CPUs on individual virtual servers takes minutes, allowing you to quickly respond to increases in demand. In addition, deploying new virtual servers takes a little more than an hour, whereas deploying a physical server may take several days.

For a medical practice there are many benefits for deploying virtualisation on their systems. The key benefits are best summarised as being growth, continuance and cost:


Virtualisation can give the medical practice or clinic a greater capacity to grow its business by simply adding more virtual servers. For instance one server with the necessary CPU capacity, RAM and disk space can use virtualisation to run:

  • File sharing
  • Practice management software
  • Organisation email systems such as Microsoft Outlook Exchange
  • SQL database server
  • Terminal Services (which enables off-site logins)

The use of virtual servers mitigates the conflicts which normally arise when these types of applications are loaded onto one operating system. The practice can also expand its systems by simply adding new virtual operating systems to its server.


The use of virtual servers can increase a practice’s ability to run their IT systems with minimal disruptions. A virtual server is a folder containing around 10 files that can be backed-up and copied just like any other files. This allows a practice’s server to be backed-up (including all configuration and settings) in a matter of minutes.

The backup can be used to move the entire virtual server to another machine if required. If there are any faults with the virtual server’s underlying hardware, which is affecting the practice’s operation, they can be quickly moved to another server or PC to ensure services are back up and running.


As mentioned earlier, deploying virtualisation is made relatively attractive as most of the entry-level vendor products are free. These entry-level products have the necessary features which allow practices to run the range of systems and applications they require, without the need to upgrade to the licensed virtual server products.

Due also to the falling prices of server hardware and its increasing capacities, most servers offered on the market these days have the capacity to effectively run virtualisation. The principal investment needed is to increase the levels of memory (RAM) and hard disks on the server. Many existing servers can also be used for virtualisation if they have the ability to add the required levels of memory and disk space.

Generally the cost benefit to a medical practice is quite favourable given the systems enhanced ability to run multiple services, add new virtual servers and mitigate the loss of services and disruption to the day-to-day running of the practice.

What are virtualisation’s challenges?

Despite all its attractions, virtualisation is not without its challenges.

While many claim that the best way to understand virtualisation is by jumping in the deep end and just doing it, one of the most important things in the process of virtualisation for any production or mission-critical system is experience. Running a single operating system can be complex in itself. There is a large amount of hardware that the operating system has to interface with and individual applications will have distinct hardware requirements that may mirror or compete with other applications. On top of juggling these issues within a single machine, there is the all-important and frequently dreaded matter of security and redundancy.

Virtualisation takes these issues and multiplies them by a factor of at least five. Disk and memory contention is a common issue for non-virtualised systems, and in a virtualised environment these resources underpin a number of guest operating systems and their performance. When considering virtualisation it is important to be aware that some systems may not work effectively for performance reasons, having experience with virtual systems will make these stand out. Experience leads to better choices of hardware for resource utilisation in a way that little else can.

Also, while virtualisation brings economies of scale in terms of physical hardware, these economies do not crossover to the management and maintenance of the guest operating systems. If you have a business that runs on a single server, virtualising the server will not solve the problem of having a single point of failure. Virtualisation may require that you re-evaluate your physical hardware capacity because of its enhanced performance needs.

Server virtualisation products

The three leading vendors for server virtualisation are VMWare, Microsoft and Citrix.

VMWare is the current dominator of the virtualisation market, with an estimated market share between 55 and 80 per cent. Microsoft is ranked next with 8.7 per cent and Xen (Citrix) rounds out the top three with around a 3 per cent stake.


This article has highlighted some of the benefits and drawbacks of virtualisation.

Virtualisation has fundamentally altered the landscape of computing infrastructure and how resources are managed and maintained. The key feature of this technology is not just the savings it brings, but its various benefits for all organisations regardless of their size.

Virtualisation can give practices and other businesses a bigger bang for their buck, a reduced need for many physical machines, lower running costs, faster deployment, increased performance stability for multiple applications and a heightened ability for business continuance.

Posted in Australian eHealth

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