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Transcript of Chapter 8
![Page 1: Chapter 8](https://reader036.fdocuments.in/reader036/viewer/2022062422/568132b4550346895d996fab/html5/thumbnails/1.jpg)
Chapter 8
Web Server Hardware and Software
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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Web Hosting Choices
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Web Hosting Choices
• 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.
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Web Hosting Choices
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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
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Test Reports on Various Web Servers
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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.
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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.
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Web Server Benchmark Software
• Web server benchmark software types are listed below:
– NetBench
– ServerBench
– SPEC SFS97
– SPECweb99
– WCAT
– WebBench
– WebStone
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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.
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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.
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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.
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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.
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Data Analysis
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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.
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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.
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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.
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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.
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Link Checking
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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.
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Remote Server Administration Tool
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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.
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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).
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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
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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.
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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.
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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.
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Microsoft Internet Information Server (IIS)
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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.
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iPlanet Enterprise Server
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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.
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Determining Web Server Hardware and Software Information
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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.
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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.
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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.
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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.
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Load-Balancing System Architecture
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Complex Load-Balancing
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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.
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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.
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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.