Sebastopol, CA--During the infancy of the Internet, a single server could easily handle the processing requirements of even one of the most popular sites of the day. Because there was no such thing as a "mission-critical" site, no one panicked when a site went down. These days, downtime has a direct dollar value associated with it and businesses can lose thousands of dollars or more in revenue for every minute their site is down, explains Tony Bourke, author of Server Load Balancing (O'Reilly, US $34.95). As a result, server load balancing--that is, distributing network load to several different machines--has become the key to web infrastructure, with nearly every major site on the Internet using it. As critical as server load balancing is, the technology is riddled with conflicting terminology and a distinct lack of resources, posing a challenge to administrators who hope to master it.
Server load balancing is a process and technology that distributes site traffic among several servers using a network-based device. Much of the information on load balancing that is available today comes from the producers of these devices in the form of vendor-specific manuals that use inconsistent terminology and are often biased toward the products they cover. Bourke says, "I wrote Server Load Balancing because there have been times when I really could have used a book on the subject, but there just wasn't anything out there. The various vendors have their manuals, of course, but they lacked certain advantages you can get from a third party."
"This book goes in-depth about the various ways load balancers can be put into a given network," Bourke continues. "This has probably been the most confusing aspect of load balancing for system administrators, and the subject that I get the most questions about. While all load balancers serve the same function (which is to balance web or other network load among available servers), there are various ways that they can be implemented in a network topology. But the problem of inconsistent or nonexistent terminology to describe these ways has added to the confusion."
Bourke explains the various ways in which load balancers can be implemented in a network, categorizes them, and most importantly, includes establishes a standard terminology that can be used to discuss the technology. "With a terminology in place," Bourke explains, "you can discuss characteristics and make comparisons. This can help you decide what is best in a given installation, or what type of installation an engineer might be troubleshooting."
In addition to explaining concepts and terminology, Server Load Balancing offers practical guidance for planning and implementing load balancing in almost any environment. It includes vendor configurations, concept overviews and implementation strategies. It also offers information and diagrams for designing, implementing and managing installations, including a discussion and quick-reference configuration guide for each of the four major vendors of load balancing products:
- Alteon WebSystems
- Cisco's CSS Series (formerly ArrowPoint)
- F5's BIG-IP
- The Foundry ServerIron series
By comparing several load balancing products, system administrators will gain a deeper understanding of the technology and how best to use it to improve network performance.
Server Load Balancing was written for system administrators who are responsible for the maintenance, troubleshooting and general use of load balancers. Bourke adds that his book contains information for generalists as well, explaining the basic concepts involved with server load balancing.
Chapter 7, "NAT-Based SLB Network Architecture," is available free online.
More information about the book, including Table of Contents, index, author bio, and samples.
A cover graphic in jpeg format.
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