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.
Online Resources:
Server Load
Balancing
By Tony Bourke
August 2001
ISBN 0-596-00050-2, 175 pages, $34.95 (US)
order@oreilly.com
1-800-998-9938
