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French Duncan, a firm of chartered accountants based in the west of Scotland, has squeezed more out of its limited IT budget by using a combination of Linux and virtual machine (VM) software, which allows multiple servers to be run from a single piece of hardware.
"We were running three physical servers and looking at getting a fourth," says Colin Selfridge, IT manager at French Duncan. "VMware's GSX Server software allows us to run three VM servers on two physical servers, combining servers such as our back-up domain controller, which is only used at certain times of the day, with SQL Server, which is used heavily."
GSX Server allows Selfridge to allocate resources such as Ram and hard disc space to each virtual machine as required. "We can use the hardware we already have to greater advantage," he says. "With space at a premium, it is also helpful to have fewer servers."
GSX Server delivers virtual servers over the top of a host operating system. French Duncan's supplier recommended running Windows over the top of Linux, and Selfridge says this improved reliability. "The Microsoft servers had to be restarted regularly. The Linux servers do not need to be restarted as often, even when running Microsoft," he says.
Selfridge says layering Microsoft virtual machines over Linux was cheaper from a licensing perspective and, compared with Microsoft, the open source operating system uses fewer resources to keep itself running, allowing more of the physical server's capabilities to be dedicated to applications.
The cost of the VM software was roughly equivalent to the cost of the new physical server French Duncan was considering buying, but Selfridge says he can now run up to 12 virtual servers on the same physical hardware without an appreciable deterioration in performance. French Duncan could achieve additional cost savings if it adds further servers, such as the Exchange server it is contemplating implementing, as the firm would only need to buy a Windows 2000 server licence but no new hardware.
The move has also simplified the back-up process. "The VM software can suspend the virtual machines to create a flat file of about 100Mbytes, which contains the entire server contents, including any applications," Selfridge says. "Being able to back-up that flat file means we can do back-ups more quickly. They are also less likely to fail because we are not doing them on the live server, which people are continuing to access."
Although this means the network is unavailable for a period overnight, the solution provides much greater resilience and availability. It takes just five or six minutes to replicate a virtual server on another machine from a back-up. Additionally, with the ARCServe back-up software running at the Linux level, Selfridge only has to license it for two physical servers and not the three VM servers.
Selfridge had no problem integrating Linux with the Microsoft-based elements of his network. In fact, French Duncan had been running a Linux-based mail server, supplied by its internet service provider, for a couple of years before the switch to GSX Server. The Linux servers now work well alongside a network attached storage (Nas) box running Windows 2000. The Nas system was bought before the move to Linux and Selfridge says he would now look to buy Linux-based storage and use Samba (a free, open source version of the Cifs file-sharing protocol) to make it appear as another shared network resource.
This ability for Linux and Windows to co-exist means French Duncan was able to make the switch to the new platform slowly. "We set the new network up but left the old one running," he says. "We were able to migrate it piecemeal over a period of about six weeks." To end-users, the network appears to be completely Microsoft-based, with a Microsoft domain controller and SQL Server database.
Selfridge can also lay to rest SMEs' concerns that open source software will not come with the necessary support. French Duncan's copy of Linux, downloaded free from Red Hat, did not come with any support bundled in, but Selfridge did not feel the need to buy support services. "It is not a techie's system any more," he says. "It has a graphical user interface and you do not have to go down to a command line. The downloads come as the equivalent of a .exe file, so it is easy to install."
Selfridge can also write configuration files for tasks such as clearing out back-up logs. "We can manage them in the same way as Windows products," he says. Similarly, the GSX Server can be administered through terminal services or through a web interface.
Selfridge is hugely impressed with the performance of open source products, but French Duncan continues to run Microsoft products on its servers and Windows and Office 2000 on its client machines because the specialised accountancy packages the firm uses rely on these products. "Many of the developers who supply those solutions are Microsoft certified partners and use Microsoft architecture," he says. "But I am investigating other open source products, such as MySQL and Openoffice, to see if they can be substituted.
"We are in no hurry to get rid of Microsoft, but we are looking at our options,. Now we are able to ask whether a particular application must have access to SQL Server or Microsoft Office, or if it will run against open source products. We can question whether new applications or upgrades will run on a different platform to Microsoft."
About the company
An independent firm of chartered accountants, French Duncan employs 100 staff, including 14 partners, across three offices in Scotland. Formed through a series of mergers and acquisitions, the company's roots go back more than 100 years and it now boasts a turnover of about £4.5m.
As well as providing traditional audit services, the firm runs a payroll bureau, insolvency and corporate finance divisions. It recently qualified to sell mortgages and also provides investment advice through its financial services division.
About the project
The challengeTo make the most of a limited IT budget and a lack of physical space when implementing a new server with increased reliability.
The solutionInstall Red Hat Linux running VMware GSX Server, allowing three virtual servers to be run on two physical servers.
- Reduced software licence costs
- Greater reliability and improved back-up
- Better allocation of existing hardware resources between servers and applications.