Desktop Deployment Case Studies, GBdirect Technical Consultancy

GBdirect is a small (approx 10 full-time equivalent staff) technical consultancy specialising in software consultancy, software development, website engineering, technical training and similar services. (NOTE: the Managing Director of GBdirect is the maintainer of this Migration Guide)

Although employing mostly technical staff, the company also has staff in sales and administrative rôles. In 1998 the systems used were predominantly based on Microsoft Windows 95. The high overhead of maintaining those systems caused a rethink and a decision was made to switch entirely to Open Source Software expect for the system used for financial bookkeeping (QuickBooks).

Linux-based systems are now used for all daily work, software development, database deployment, document preparation (including training manuals of up to 500/600 pages in size) and routine office applications (OpenOffice.org).

Since the company is clearly closely related to this Migration Guide and now makes a good part of its income from consulting in this area, it is unlikely to be considered an entirely unbiased source of authority. All the same, the decision to switch was made on grounds of reliablity and cost; the switch to providing consulting services came only after the experience proved to be a good one. The purpose of this case study is to highlight the use of thin-client technology within the business

Linux Thin Client Deployment

When GBdirect switched to using Linux for all of its company desktops, the first move was to replace the Windows software running on all of the desktop computers with Linux. The first version to be installed was Red Hat 5.2 running the standard graphical interface based on the X Window System. In those early days it wasn't all plain sailing but the core services needed by the business (email, web access, software development, document preparation) were all catered for well enough that the experiment was deemed to be a success. The office administrator retained the use of a Windows-based PC and this provided access to the software for which there was no good analogue in the Linux world. VNC proved itself to be a very useful tool when there was an occasional need to use a Windows program from a Linux desktop.

The desktop PCs still proved to be a nuisance. Whenever new releases of tools (the web browser was a particularly important example) appeared, each PC had to be upgraded to the new release level. Backup systems had to be put in place for each PC and file sharing amongst members of staff was a mild incovenience. Since the deployment had been done in a rather unimaginative way (quick and dirty) there wasn't the appropriate use of shared filesystems and NIS directory services that a better installation would have chosen.

As soon as the opportunity arose, a long-standing desire to switch to a thin-client model was chosen. The X Window System is the universal choice of windowing system in the Linux world. This is inherently a network-based system, designed specifically for the case where the window display device is remote: on the other side of a network from the place where the application software is running. Typical Linux desktop systems don't make use of that but they miss an opportunity. One of the most popular ways of implementing thin-client systems with Linux is to use the LTSP package. LTSP allows any ordinary PC with a network and graphics card to use remote-boot facilities to turn itself into a working X Window System display; it can be booted from a floppy disk or a network card with built-in or add-on remote-boot services (most modern cards support this).

The company now uses thin clients exclusively. Cast-off PCs (Compaq Prolineas) are used as fanless, diskless workstations, all served by a single main server. The benefits of using these workstations include:

• Zero maintenance
• Hotdesking for staff
• Centralised systems administration
• Lower power consumption and heat production (very green)
• Landfill sites not clogged with cast-off PCs (even greener)

A single server of modest power is estimated to have enough resources to service some 20-30 desktops. We also know that the University of Leeds (no link unfortunately) supports two rooms of workstations servicing 250 simultaneous student users on a single 4-way Intel Xeon server.

More background on the use of X terminals at GBdirect can be found here.

In summary:

• Anyone considering desktop deployment must look at thin client models
• Awesome cost and maintenance savings can be had
• A single central server can support from tens up to hundreds of users
• This is very different world from the proprietary one
• The X Window System is designed for thin client use, it's not a bolt-on extra

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