6. Advanced Web-Hosting Methods

6. Advanced Web-Hosting Methods
During the last several years, Web hosting has evolved from simple one-computer
system architectures to redundant, load-balanced server farms. A server farm is a
network of computer systems. As a Web site demands more and more system
resources, the traditional hosting environment is constrained by the limited
amount of av ailable resources. There are two basic means of providing more
resources: a larger computer system or a distributed computer environment. To
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provide redundancy and scalability, the distributed computer environment is the
preferred method of expanding system resources.
The simplest distributed computer environment consists of two identical Web
servers on the same local-area network (LAN) with a load-balancing device (see
Figure 3
). The load-balancing device is the gateway for all traffic entering and
leaving the Web servers. The load balancer directs the incoming traffic to the best
performing Web server, to alleviate all resource bottlenecks. With the load
balancer as the gateway, the two Web servers appear as one large computing
environment to all end-users on the Internet. This simple distributed computer
environment can be expanded to accommodate more Web servers, providing
greater scalability and consistently high performance levels.
Figure 3. Load Balancing Two Web Servers
The simple distributed-computer environment provides a method for increasing
the available computer-system resources, but it will not prevent performance
problems associated with specific network issues within the LAN or with the
Internet connection at that specific location. To overcome local network
problems, Web hosting has continued to evolve into a geographically distributed
computing–environment architecture.
By distributing the traffic of a Web site across multiple servers located in
dispersed geographic locations, system resources can be added without
interruptions in the Web-hosting service, and the Web site can always be
available despite LAN or Internet-connection problems. Moreover, with
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intelligent wide-area network (WAN) load balancing, Web-site performance will
increase for all visitors, regardless of their geographic location.
Figure 4
illustrates Web hosting in a geographically distributed computing
environment.
Figure 4. Two Site Architectures
Self-Test
1. Who invented the World Wide Web?
a. Albert Einstein
b. Marc Andreessen
c. Tim Berners-Lee
d. Bill Gates
2. With what server does the Web browser communicate to find the IP number
of a Web site?
a. Web server
b. DNS server
c. FTP server
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