Linux Terminal Servers for Any Business
A Linux Terminal Server offers any business an elegant and cost-effective way to integrate the power of open source. In this article, I review some basics of network topology and offer suggestions about how to install a prototype server. I top it off with some tips for business-specific installations and configuration guidance.
A Linux Terminal Server allows almost any business to gain the benefits of open source and the power of Linux immediately. What makes an LTS distinct is that it integrates well, without burden to infrastructure or people. Moreover, the performance of an LTS dramatically showcases Linux power. One LTS can serve graphics and applications to many desktop PCs simultaneously.
By placing the LTS into an existing subnet, colleagues can access the many useful applications and features with almost no effort—and at their convenience.
A great deal of effort has been put into the Linux Terminal Server Project (LTSP) to make it seamless. LTS simplifies installation by isolating the integration work exclusively on the server.
With an LTS, even the most hesitant users experience the benefits of open source in their organizational context. No re-installs are required. No major licensing or policy changes. And most important of all, the financial costs are negligible.
As an illustration, I recently found that a local real-estate company had needs that perfectly matched with an LTS. Among the many available applications, I demonstrated the ease of The GIMP to alter photos downloaded from the agents' cameras. Then I included simple bash scripts to automate the uploading of the enhanced images to their Web site. The GIMP exemplifies the many outstanding open-source programs they could access easily through the LTS.
This simple example demonstrates how a business that never considered Linux or open source could quickly gain access to applications with very little cost in time or money. Above all, the agents could access the LTS from their own desktops without any alterations.
Now, let me share some of the basics of integrating an LTS into your business.
First, choose your network topology and server based on your specific business context. Next, choose your method of installation and follow the on-line instructions. Finally, configure your server to support thin-client connections. You'll find that most installations work smoothly and quickly. To help guide your steps, I include tips for some of the more essential configurations.
If you look at most of the existing installations of LTS, you'll find that they implement a closed subnet configuration. In such a configuration, the LTS serves thin clients within its own controlled subnet and provides routing to the overall organization's network through a second Ethernet port.
Utilize this closed subnet configuration to isolate thin clients, such as in a work lab. Sometimes, this configuration also provides a reasonable solution for business, where a team or department needs the access and features of an LTS.
This is a superb solution when your business starts a new department and wants to manage hardware and software licensing costs tightly, or when capital budgets could better be used for staffing. In this scenario, the business gains dramatically as LTSP does not require robust desktop PCs.
They may exist as outdated PCs or as simple diskless workstations. Often such connectivity costs less than $300 per seat. Ironically, it costs more per seat just for software licensing in most business situations.
As shown in Figure 2, the LTS also can benefit an organization when installed into an existing subnet. The other computers do not rely on the LTS, but they gain access to the LTS and its many applications and features.
I assume in both cases, your LTS sits snuggly behind your business firewall. Also, both examples allow authentication servers, network file stores and broadband connectivity through additional tools like Samba and WinBind. However, I recommend you begin with a simplified installation. You always can adjust or expand the LTS' role and features once operational.
Figure 2 represents a prototype LTS that offers anyone on the subnet access while remaining largely “invisible” to the other servers on the network. In most cases, this setup requires only one Ethernet connection and reserved IP addresses for a particular subnet.
Now, I'll share some specifications that will help you choose a reasonable business server.
For every simultaneous thin client you want to connect, you should have about 128MB of RAM. The more the better, but this provides a good start. For a real-world example, I've seen that a thin client running KDE with OpenOffice.org Writer and a Firefox browser will use about 115MB.
I recommend that you use at minimum a 7,200rpm disk drive with a decent onboard cache. SATA or SCSI are standard for most business servers, and you should use these if possible.
Obviously, if you can acquire a more powerful processor or dual-processing capability, so much the better. I've even seen 2.4GHz processors with plenty of RAM (2GB+) do quite well. If you must make a choice, place emphasis on RAM over processor speed.
The folks at the LTSP.org have done a phenomenal job of supporting volumes of configurations and flavor variances. However, as a basic guide, using PCI cards and Digital Signal Processor (DSP)-based sound cards will ensure an easier integration.
Once you've decided on the topology and server, choose your installation method.
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