Virtual solutions

Judging by the column inches devoted to it, virtualisation is one of the hottest technologies around. But do you really know what it does and, more importantly, what it has to offer a small business?

In this feature we’ll help you to fill any gaps in your knowledge, providing a full picture of what’s meant by virtualisation, its benefits for small businesses and the products available to realise them.

Virtualisation explained
The term virtualisation can be applied to many subtly different technologies, but all are based on the same concept – the use of software to emulate another hardware or software resource.

Hard disks, for example, have long been virtualised through the use of software to sub-divide available storage space into partitions, each of which can be treated as an individual physical drive. An operating system is in fact a form of virtualisation, although nowadays the term is more commonly used to describe the virtualisation of a complete PC or server – a virtual machine (VM) – which can be run alongside other VMs on the same host hardware.

Virtual machines run like applications, sharing access to the physical processors, memory, disk space and other resources on the host system. As far as each VM is concerned, however, it appears to have sole access to the resources allocated to it. It can therefore run a standard operating system, installed, configured and used in exactly the same way as on a ‘real’ machine.

Virtual benefits
So, what are the benefits? Well, it depends on who you are.

If you’re a software developer, virtualisation lets you test and debug your code on all the platforms you want to support, without buying or configuring lots of kit. It also makes it easier to handle inevitable lock-ups and crashes, as they won’t affect other virtual machines. If you get really stuck, you can simply start again with another copy of the VM.

Virtualisation also allows you to check out new applications, updates and patches without affecting production systems, and it makes better use of hardware resources, particularly servers, many of which sit doing very little most of the time. It’s this efficiency that makes most small-business managers take notice.

For example, virtualisation would allow you to take existing file and print, email and database servers – possibly running on out-of-date hardware – and consolidate them onto a single machine.

You can do that anyway, but the virtual approach means you don’t have to worry about compatibility, doing away with the need to upgrade or change your applications to get them to work together. Instead you migrate the existing physical setups lock stock and barrel to separate VMs. Tools to do this are available from most virtualisation vendors.

Virtualisation also offers savings in terms of power and cooling, and there are availability and management benefits too. Virtual machines are defined in files that can be copied and cloned as needed to bring new servers online in minutes.

You can balance loads across servers more easily, and recover faster from system failures and other problems. Most virtualisation tools, for example, let you take snapshots of running VMs that can be used for backups or to roll back configuration changes that have caused problems.

On the downside you will have to obtain, install and manage the virtualisation software, as it isn’t commonly included as part of the operating system. But it’s not that difficult and there are lots of good products to choose from, many designed specifically for small businesses.

Virtual products
The market leader is VMWare (part of EMC) with the biggest and longest-established portfolio of products, followed by Microsoft and a number of smaller developers. Most notable of those is Xen Source, whose open-source Xen virtualisation software is bundled with several Linux distributions.

Many of the products are now free, and a good starting point is the free VMWare Player, which you can download and use to run pre-built virtual machines (see Virtual appliances explained, later).

To create virtual machines of your own, you’ll need VMWare Server, which is also a free download. VMWare Server is also more scalable (it supports two-way virtual SMP) and it comes with tools to take VM snapshots for backup and recovery.

VMWare Player and Server are both available for use on Windows and Linux hosts and include support for a wide range of Windows, Linux and Unix guest operating systems, including 64-bit implementations.

Among its chargeable products, VMWare Workstation is aimed at application developers and has tools to debug code and simulate a variety of network types. For all-out production use, VMWare Infrastructure 3 is based on the highly scalable VMWare ESX Server platform and requires servers with a minimum of two processors. It is installed directly onto the server hardware rather than a host OS.