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Serve the pages

With the Web becoming central for business and communication, it is imperative that your enterprise has a Web presence. Read on for some tips on selecting the components that go into a Web server. by Soutiman Das Gupta

Most brick-and-mortar companies in India have adopted the Web in some form or the other to enhance their business. It may be in the form of a basic HTTP (Hyper Text Transfer Protocol) enabled website with absolutely no 'frills'. This can be referred to as a 'Web brochure'. Or, it may be in the form of a site, to which the company has extended a part of its services. Through the site, the company can receive orders, post information, and allow basic interaction.

Some Indian companies do all their business online and offer services like trading, shopping, and auction. For these organizations, the network is the business. It means that the entire business runs on networking elements like servers, routers, switches and backbone connectivity.

No matter what kind of business you are in, if you have Web presence of any nature, it's important to keep the website and facilities available for all online functions. And in order to do that, you need to have a dedicated server for serving Web pages.

The basics
A Web server allows you to serve content over the Internet using HTML. The server hardware configuration is not very different from any other application or database server configuration. It allows a site to be accessed from it with the help of Web server software. The Web server accepts requests from browsers like Netscape and Internet Explorer and returns the appropriate HTML documents. A number of server-side technologies can be used to increase the power of the server beyond its ability to deliver standard HTML pages. The technologies are CGI (Computer Graphics Interface) scripts, XML (Extensible Markup Language), ASPs (Active Server Pages), and SSL (Secure Sockets Layer) for security.

The Web server receives a request for a Web page like http://www.networkmagazineindia.com/index.html and maps the URL to a local file on the host server. In this case, the file 'index.html' is somewhere on the host file system. The server loads this file from disk and serves it out across the network to the user's Web browser. This entire exchange is mediated by the browser and server talking to each other using HTTP.

Processor power
When it comes to processors in the Web serving space, Intel (with its CISC-based processors namely the Itanium and Xeon) and Sun (with its RISC-based UltraSparc processors) cater to the Web serving space.

So which would be the right processor for your Web server? Depends on the cost. If you are on a tight budget or prefer Windows or Linux as your server OS, then you will have to stick with an Intel box.

But if you have the resources and the expertise to manage Solaris, a Sun UltraSparc would be highly recommended. Sun UltraSparc-based servers are bundled with Solaris OS.

If you are expecting heavy traffic on your website, it is recommended to go in for two or more processors in SMP (Symmetric Multi-processing) architecture. A SMP architecture allows multiple CPUs residing in one cabinet to share the same memory. SMP systems provide scalability because additional processors can be added to support increase in transaction volume.

Memory booster
Memory (read RAM) is a function of the OS you plan to use as well as the traffic you expect on your website. When it comes to OS, it may be a good idea to over-estimate the amount of memory required. OS developers publish guidelines that advise on the amount of RAM needed to support a given number of users.

For a Web server you should consider 256 MB as the bare minimum. If you expect higher number of users and heavy activity in peak traffic hours, it's advisable to have more RAM. EDO (Extended Data Out) RAM gives good performance because it eliminates wait states by keeping the output buffer active until the next cycle begins. SDRAM (Synchronous DRAM) chips are also preferred. SDRAM is fast enough to be synchronized with the CPU's clock and eliminates wait states. At the same time you'll need ECC (Error Checking and Correction) memory rather than ordinary parity-checked RAM. Systems that use parity RAM simply stop when a memory fault occurs while ECC RAM detects and fixes the error while the server works.

Store it up
The next area to concentrate on is disk storage. Storage is not just about high speed and capacity, but also about features like high availability and a system that warns of faults and tolerates individual disk failures. There are two types of hard disks available: EIDE and SCSI. SCSI disks are faster and you can attach up to 15 disks to one controller compared with just four with EIDE. Also SCSI hard disks are faster. This makes SCSI drives the preferred choice for Web servers.

Another consideration in favor of SCSI is the number of channels. Multiple channels can improve performance and add the much-needed hardware redundancy. For example, two SCSI channels allow you to duplex drives and mirror the controllers and disks attached to them. By doing this, you can have online backup if any storage hardware fails.

The OS
An OS makes a big difference. Processor, RAM, and bandwidth usage in a system could increase or decrease with different OSs. There isn't a 'one size fits all' solution, but different hardware combinations and applications might favor certain OSs. There are three leading products to choose from: NetWare from Novell, Microsoft Windows family, and Unix along with its variants like Solaris, SCO, and Red Hat Linux.

Selecting an OS depends on your requirements, the server processor and your budget. If you go for an Intel box, your choice usually narrows down to NetWare, Windows NT/2000 or Linux. If you are on a tight budget, then it is recommended to go for Linux as your server OS, after all it's free. When it comes to Windows, it is recommended to go for 2000 over the older NT, since 2000 features many enhancements that make it an ideal OS for running your Web serving software. Sun UltraSparc-based servers come with Solaris, a Unix variant.

Serving software
The Web serving software sits on the top of the OS and serves Web pages on request. Choosing a Web serving software depends on three important factors: your budget, the OS you use and the functionality you are looking for.

Nowadays most operating systems come with inbuilt Web serving software. An example would be IIS (Internet Information Server) which comes with Windows 2000. Then there are plenty of free Web serving software, popular among them being Apache, that provide good functionality.

Soutiman Das Gupta can be reached at soutimand@networkmagazineindia.com