Desktop and server virtualisation is achieved with software from vendors such as Microsoft or VMware. These products enable a larger server to be divided up into small virtual machines, which allows an organisation to extract get the most use from physical machines. By installing a minimum of two servers, resilience is automatically built-in, ensuring that there is no single point of failure.
For the past eight years, server virtualisation has been the main strategy for organisations that wanted to reduce server and operational costs. In recent years, this has extended to the desktop with virtual desktop infrastructure (VDI). Many organisations have adopted VDI as the first phase of machine virtualisation because of the savings that can be achieved by replacing PCs -- or not buying new ones. These machines are just a commodity, so any cost-saving technique is now widely accepted.
VDI allows users to work from any location. Because employees are not tied to a PC in the office and can access a desktop virtual machine from any location, organisations can allow personnel to work from home when it's not possible to get to the office as
Virtualisation cost savings
The main benefits of server virtualisation are reduced number of server purchases and availability at no cost. As a general guide, a server costs £2,500. A virtual machine (VM) running on a larger server that has been divided into many VMs typically costs £1,100 per virtual machine. For VDI deployments where servers can be divided up many more times, the cost per VM is typically £150 -- about half the cost of a desktop PC.
Another benefit of VDI and server virtualisation is the ability to centralise data, making backup easier and lowering costs. Consolidating desktops into a VDI environment brings the biggest saving, and that is concurrent usage. In a PC environment, if you have 100 desktop computers, you must have 100 licenses for products like Microsoft Office.
With VDI, it is possible to run fewer virtual machines than users, because in all organisations there will be some workers at meetings, on holiday or off sick. This method of desktop delivery is called dynamic allocation. This means when a user logs in, a VM is allocated for the time he is working. When the user is finished, the VM is returned to the pool so someone else can use it. With a VDI implementation, all user data is stored on a file server so each machine can be used by different people.
Virtualisation allows significant reductions in computing power for any organisation, and as long as the implementation is designed effectively, the return on investment can be measured in months. A usual payback period for server virtualisation is eight to 14 months, and for VDI deployments, the average payback period is five to seven months.
It is easily possible to combine server and desktop virtualisation. In fact, it is a best practice to do so, as the workloads on each type of virtual machine are different, which helps utilise the physical resources to the maximum.
VMware was the first vendor to introduce virtualisation technology in 2000. Microsoft has only recently entered the market. Citrix purchased the Xen Server virtualisation platform in 2007.
With the growth in server hardware performance, virtualisation has become a major topic for all types of organisations, from small and medium-sized businesses to corporate-sized companies and the public sector.
Cam Merrett is director of Pulsar Cloud Ltd. and a contributor to SeachVirtualDataCentre.co.uk. Pulsar is a U.K.-based heterogeneous VDI consultancy. Vendor partners include the likes of VMware, Citrix, IBM, Sun and Quest.
This was first published in November 2009