Desktop virtualisation: stretching budgets and cutting costs
There are also some hidden savings to consider. One PC uses significantly less power than six; this represents a substantial drop in the cost of powering your IT. There’s also a potential saving on infrastructure costs; six clients running from one multi-seat server would require only one physical network point, and that’s potentially a great way of making use of the odd network socket you have in a room while expanding the reach of IT in your school.
One question that always comes up with virtualisation is what happens when things go wrong? If we have a problem with a PC in a typical ICT suite, then one student per lesson is going to lose out. If we have a PC being used by six, won’t they all miss out? Unfortunately, the answer is “yes”, but there are things we can do to protect against this.
Two of the most common hardware problems we face are faulty hard drives and power supplies, and you can go a long way towards combating these in your server by investing in a RAID setup and a redundant power supply. Besides, a key point to remember is that, by replacing multiple PCs with a single system, you’re also reducing the amount of machines that can go wrong. You still run the risk of faults with monitors, keyboards and mice, but this would be the same regardless of the hardware you’re working with.
The second question we face is performance. How does one PC hold up to running multiple applications from multiple users at the same time? The answer is that it does so remarkably well. It’s wise to approach virtualisation with some scepticism, but let’s face it: modern PCs are usually overpowered for everyday ICT tasks, and plenty of processing power goes to waste. Even now, getting multiple users on one machine doing video editing and other similarly resource-intensive tasks is never going to work, but if your pupils are only using Office and a browser, then these applications will work well on a modestly specified host.
For example, in 2010 IT consultant John Goodier implemented an eight-seat Windows MultiPoint solution at Dowson Primary School, Hyde, using LG network monitors and a server with a Core i7 processor and 12GB of RAM. “We hammered the eight LG screens and let the kids run whatever they liked,” says Goodier. “The result was a bombardment of Flash games and video. With all eight screens running flat-out, processor time never went above 11%, with around 2.5 to 3GB of memory used. I have to say the performance seemed outstanding. In fact, you’d never know you weren’t logged onto a normal PC.”
Licensing is another problem area. Many software vendors simply don’t have a licensing model for virtual desktops, although the situation is rapidly changing as virtualisation grows in public services and enterprise. A simple rule of thumb is to treat each client as if it was a full PC. Don’t presume that because you’re only installing a piece of software on one physical PC, you need one licence. After all, nobody ever faced a fine or legal action for being over-licensed!