1. Chapter 8 Web Server Hardware and Software

2. Learning Objectives In this chapter, you will learn about: Web server hardware considerations Measuring the performance of Web server hardware The way that individual computers are combined to provide large-scale Web services Web server software including Apache, Microsoft Internet Information Server, and iPlanet Web Server. Other software that works with Web server software to accomplish the basic operations of a Web site.

3. Web Server Hardware and Performance Evaluation Today a Web site may be the first place customers go to conduct business with traditional companies, while electronic commerce sites have become the main business focus for many organizations. The two main ingredients in a Web server are its hardware and it Web server software.

4. Types of Web Sites An important first step in planning a Web server is to determine what the company wants to accomplish with the server. The company must estimate how many visitors will be connecting to the Web site and what types of files will be delivered through the site. Companies create Web sites in a wide variety of forms including simple development sites, intranets, information-only sites for customers, business-to- business portals, storefronts, or content-delivery.

5. Development Sites The simplest Web site and the least costly to implement is a development site. A development site can reside on an existing PC and can be developed with low-cost Web site building tools, such as Microsoft FrontPage or Macromedia Dreamweaver. Testers can access the site through their PCs on the existing LAN.

6. Intranets Corporate intranets house internal memos, corporate policy handbooks, expense account worksheets, budgets, newsletters, and a variety of other corporate documents. Intranets are shielded from the Internet, they do not require additional security software to protect them against threats from outside the company.

7. Transaction-Processing Sites Transaction-processing sites, such as business-to- business and business-to-consumer electronic commerce sites must be available 24 hours a day, seven days a week; that is, they must be high- reliability servers. Transaction-processing sites must also have spare server computers to handle high traffic volumes. Transaction-processing sites must also run security software.

8. Content Delivery Sites Content delivery sites, such as The Wall Street Journal, The New York Times, and C-Net, sell and deliver content, such as news, histories, summaries, and other digital information. Content must be presented rapidly on the visitor’s screen. Visitors must be able to locate articles quickly with a fast and precise search engine.

9. Web Hosting Choices The company must decide whether to run servers in-house or through third-party Web and e-commerce providers. Companies should consider: –scalability of e-commerce –bandwidth of the Web site –a local third-party ISP Contact Web Host Guild (WHG) for help.

10. Web Hosting Choices

11. When making Web server hosting decisions, a company should ask whether the hardware, or platform and software combination, can be upgraded when the traffic on its site increases. Using a service provider’s shared or dedicated hosting services instead of building an in-house server or using a co-location service means that the staffing burden shifts from the company to the Web host.

12. Web Hosting Choices

13. Operating Systems for Web Servers Hardware decisions go hand in hand with operating system and application server software choices. Companies should consider: –Speed -- A fast server is better than a slower one –Internal and external traffic to occur on the server –Scalability of the server hardware

14. Test Reports on Various Web Servers

15. Building a Scalable E-commerce Systems Three layers in E-commerce systems: Web server layer Middle-tier layer Backend layer An application server is a middle-tier software and hardware combination that lies between the Internet and a corporate backend server.

16. Web Server Performance Evaluation Benchmarking is a form of testing used to compare the performance of hardware and software. Hardware and operating systems are key areas for benchmarking. The speed of its connection can affect a Web server’s performance. Throughput and response time can be used to measure a server’s Web page delivery capability.

17. Web Server Benchmark Software Web server benchmark software types are listed below: –NetBench –ServerBench –SPEC SFS97 –SPECweb99 –WCAT –WebBench –WebStone

18. Desirable Features of Web Servers Web servers are located on the Internet or intranets, usually behind firewalls. The duties and features of Web servers differ depending on whether they are publicly accessible. Web server software features depend on the software package being used.

19. Core Capabilities The most fundamental duty of a Web server is to process and respond to Web client requests that are sent using the HTTP protocol. For dynamic pages, the server uses an architecture with three or more tiers that invokes other programs.

20. Indexing and Searching Search engine and indexing programs are important elements of many Web servers. Search engines, or search tools, search either a specific site or the entire Web for requested documents. An indexing program can provide full-text indexing that generates an index for all documents stored on a server.

21. Data Analysis Web servers can capture visitor information, including data about who is visiting a Web site, how long the visitor’s Web browser viewed the site, the date and time of each visit, and which pages were displayed. Two of the most popular Web log file analysis programs are the Analog Web server log file analyzer and the WebTrends Web server log file analyzer. Figure 8-4 shows part of WebTrends log file analysis report.

22. Data Analysis

23. Site Management Tools FrontPage has some site management capabilities. HomeSite is a site management tool that validates graphics, computes page-download times for modem connection, validates links, and validates HTML codes.

24. Site Management Tools Application construction uses Web editors and extensions to produce Web pages. Some Web development systems provide simple tools to create Web pages. Some tools can be used to create dynamic features without the need to know CGI or use API coding.

25. Link Checking A link checker examines each page on the site and reports on any URLs that are broken, that seem to be broken, or that are in some way incorrect. An orphan file is a file on a Web site that is not linked to any page. Other important site management features include script checking and HTML validation. A dead link, when clicked, displays an error message rather than a Web page.

26. Link Checking Free link-checking and Web site validation programs, such as Elsop Linkscan, can be launched by entering the address of a Web site’s home page and checking a few boxes. Commercial site checkers, such as Big Brother software from Watchfire, produce more comprehensive results and more detailed site analyses than do the free products.

27. Link Checking

28. Remote Server Administration With remote server administration, a Web site administrator can control a Web site from any Internet-connected computer. Although all Web sites provide administrative controls, it is convenient for an administrator to be able to fix the server from wherever he or she happens to be.

29. Remote Server Administration Tool

30. Dynamic Content Dynamic content is nonstatic information constructed in response to a Web client’s request. Using Open DataBase Connectivity (ODBC), the Web server can assemble information from disparate database systems. Active server pages (ASP) is a server-side scripting mechanism to build dynamic sites and Web applications.

31. Dynamic Content Most Web sites today provide dynamic Web pages using an approach called server-side scripting. In server-side scripting, programs running on the Web server create Web pages before sending them back to the requesting Web clients as parts of response messages. Microsoft uses Active server pages (ASP). Sun uses Java server pages (JSP). Apache developed Hypertext Preprocessor (PHP).

32. Web Server Software There are two distinct Web servers in the market: intranet servers and public Web servers. Three of the most popular Web server programs are: Apache HTTP Server Microsoft Internet Information Server Netscape Enterprise Server

33. Apache HTTP Server The Apache HTTP Server is free and performs efficiently. Apache runs on many operating systems and the hardware that supports them. Apache has a built-in search engine and HTML authoring tools and supports FTP.

34. Apache HTTP Server Apache can be managed from either a server console or a Web server. Apache supports Server Side Includes (SSI), Active server pages and Java Servlets.

35. Microsoft Internet Information Server (IIS) IIS comes bundled with Microsoft’s Windows NT Server and 2000 Server operating systems. IIS includes an integrated search engine. IIS supports FTP, permits administration from a remote browser. IIS combines HTML pages, ActiveX components, and scripts to produce dynamic pages.

36. Microsoft Internet Information Server (IIS)

37. iPlanet Enterprise Server The iPlanet enterprise server runs on such operating systems as AIX, Digital UNIX, HP-UX, Irix, Solaris, and Windows NT. iPlanet Web server provides a powerful development environment that supports development of Web- based applications that can run on the Internet, an intranet, or an extranet. iPlanet Web server’s management tools allow administrators to manage users and monitor server activity interactively.

38. iPlanet Enterprise Server

39. Determining Web Server Hardware and Software Information You can determine the type of hardware and software most Web sites are running by visiting Netcraft. Netcraft software examines the designated Web site and returns both the Web server hardware and software information.

40. Determining Web Server Hardware and Software Information

41. Server Architectures and Server Utilities Companies that operate more than one Web server must decide how to configure their servers to provide site visitors with the best service possible. The different ways that servers can be connected to each other and to related hardware, such as routers and switches, is called server architecture.

42. Web Server Architectures Large electronic commerce Web sites must deliver millions of individual Web pages every day. They must also process thousands of customer and vendor transactions each day. The large collection of servers that these sites have are called server farms.

43. Web Server Architectures One approach to Web server architecture is called a centralized architecture, which uses a few very large and very fast computers. Another approach is a decentralized architecture, which uses a large number of servers. Most large decentralized sites use load-balancing systems.

44. Load-Balancing Systems A load-balancing switch is a piece of network hardware that monitors the workloads of the servers attached to it and assigns incoming Web traffic to the server that has the most available capacity. In a simple load-balancing system, the traffic that enters the site from the Internet, encounters the load- balancing switch, which then directs the traffic to the Web server best able to handle the traffic.

45. Load-Balancing System Architecture

46. Complex Load-Balancing

47. Search Engines A search engine is a special kind of Web page software that finds other Web pages that match a word or phrase you entered. A Web directory is a listing of hyperlinks to Web pages that is organized into hierarchical categories. Search engines contain three major parts: spider, index, and utility.

48. Intelligent Agents Software agents have been in use for a number of years. An intelligent agent is a program that performs functions, such as information gathering, information filtering, or mediation running, in the background on behalf of a person or entity. Research reveals that software agents will become extremely important in the electronic commerce field sooner than later.

49. Intelligent Agents Because software agents are always running in the background they can help reduce the workload that people normally take on in locating, thinking about, negotiating, and purchasing goods and services. Examples of agent systems include Best Web and MySimon.