Server Load Balancing

Features

• Cover Type: Paperback with 208 pages
• Published by: O'Reilly Media, Inc.
• Edition: 1st Edition August 2001
• Written in: English
• ISBN 10 Number: 0596000502
• ISBN 13 Number: 978-0596000509
• Book Dimensions: 9 x 6.9 x 0.6 inches
• Weighs: 11.4 ounces

Product Review
An increasing number of shops are putting clustering and load-balancing technologies into place so as to provide high availability and an economic way to scale server capacity. The slender Server Load Balancing explains the state of the art in multiple-server technologies implemented at Layers 4 and 5 on the OSI network model. Though author Tony Bourke includes a fair bit of good information on configuring four commercial load-balancing solutions, the most valuable part of his work is his high-level discussions of how load balancing fits into a greater network environment, and his explanations of the relative merits of alternative approaches to the problem. A comparison of flat-based solutions with designs based on Network Address Translation (NAT) is part of this book's value; further appeal takes the form of dozens of network diagrams that document typical working solutions.

Bourke shows his familiarity with real-life design constraints by documenting various load-balancing solutions and pointing out what each can do for an organization--he points out that a host that implements a NAT-based balancing solution can double as a firewall, thereby saving some money that would have been required for a dedicated security device. He also provides introductory material on the competing solutions' administration interfaces, enabling implementers to get a head start on their work without wading into vendor documentation. --David Wall

Topics covered: The problems presented by requirements for high availability and failover, and the solutions that server load balancing can provide. In addition to general information on flat- and NAT-based load balancing solutions, this book documents strategies for implementing Alteon WebSystems, Cisco CSS, F5 BIG-IP, and Foundry ServerIron.

Book Description
Load balancing improves network performance by distributing traffic efficiently so that individual servers are not overwhelmed by sudden fluctuations in activity. Server Load Balancing is a guide to this critical component of high availability, clustering, and fault tolerance, all of which provide the infrastructure for reliable Internet sites and large corporate networks. Much of the information on load balancing comes from vendor-specific manuals that use inconsistent terminology and are often biased toward the products they cover. Server Load Balancing explains to engineers and technicians the concepts and terminology of load balancing and offers practical guidance for planning and implementing it in almost any environment. It includes a configuration guide with diagrams and sample configurations for installing, configuring, and maintaining products from the four major vendors:

• Alteon WebSystems
• Cisco's CSS Series (formerly ArrowPoint)
• F5's BIG-IP
• the Foundry ServerIron series

By comparing several load balancing products, you'll gain a deeper understanding of the technology and how best to use it to improve your network performance. No system administrator responsible for traffic management should be without this practical guide.

Reader Reviews
This book gives an organized but purely descriptive overview of server load balancing and should be helpful to anyone who is approaching the subject for the first time but does not require quantitative assessments of the different methods for doing server load balancing. It is written for the network administrator, but anyone, including network managers should find it helpful. Network engineers may find the treatment too qualitative, but it could be supplemented by more rigorous material if needed. Chapter 1 is a brief overview of the history of load balancing and why it is needed in Internet environments. DNS-based, firewall, and global server load balancing are briefly discussed, along with clustering. This is followed in chapter 2 by a brief review of the OSI model and the different components involved in server load balancing. The author cautions that the use of VRRP (Virtual Router Redundancy Protocol) may cause problems if the load balancers become isolated from each other, but does not give any historical or test examples of this. The same holds true for his caution on the use of fail-over cables. The discussion becomes a little more detailed in chapter 3, wherein the author discusses the actual functioning of a server load balancer. Direct server return is discussed, with its use of MAC address translation and loopback interfaces. Both server-based and switch-based load balancers are briefly discussed, but the author does not want to commit to which is the better architecture. The inclusion of some benchmarking studies would be helpful here. Performance metrics, such as connections per second, total concurrent connections, and throughput are discussed in chapter 4. Although the discussion is purely descriptive, the author does give a "metrics matrix" that outlines what metrics are important for different types of traffic. The author gets down to describing the network infrastructure needed to do server load balancing in chapter 5. The different possibilities for network infrastructure are classified according to the IP configuration (flat-based or NAT-based), the return path (bridge path, route path, or DSR), and physical connectivity (one-armed or two-armed). The advantages of the different types of SLB architectures are discussed briefly, but no real test cases or benchmarking studies are included. The details of flat-based SLB network architectures are discussed in chapter 6. The simplicity of this architecture is emphasized, along with its ability to pass FTP and stream traffic more readily (no real examples given however). I did not read the rest of the book which covers administrative matters, and so its review will be omitted. Comment | | (Report this)