Scalable Internet Architectures

279 Pages·2006·2.367 MB·English

by  Schlossnagle, Theo

Scalable Internet
Architectures
This page intentionally left blank
Scalable Internet
Architectures
Theo Schlossnagle
DEVELOPER’S
LIBRARY
Sams Publishing,800 East 96th Street,Indianapolis,Indiana 46240 USA
Scalable Internet Architectures Acquisitions Editor
Copyright 2007 by Sams Publishing Shelley Johnston
All rights reserved.No part of this book shall be reproduced,stored in a
Development Editor
retrieval system,or transmitted by any means,electronic,mechanical,
Damon Jordan
photocopying,recording,or otherwise,without written permission from
the publisher.No patent liability is assumed with respect to the use of the
Managing Editor
information contained herein.Although every precaution has been taken
in the preparation of this book,the publisher and author assume no Gina Kanouse
responsibility for errors or omissions.Nor is any liability assumed for
Project Editor
damages resulting from the use of the information contained herein.
Andy Beaster
International Standard Book Number:0-672-32699-X
Library of Congress Catalog Card Number:2004092644 Copy Editor
Printed in the United States of America Geneil Breeze
First Printing:July 2006
Indexer
09 08 07 06 4 3 2 1
Larry Sweazy
Trademarks
Proofreader
All terms mentioned in this book that are known to be trademarks or Kathy Bidwell
service marks have been appropriately capitalized.Sams Publishing cannot
attest to the accuracy of this information.Use of a term in this book should Technical Editors
not be regarded as affecting the validity of any trademark or service mark. Alec Peterson
Kevin Murphy
Warning and Disclaimer
Every effort has been made to make this book as complete and as accurate Publishing Coordinator
as possible,but no warranty or fitness is implied.The information provided Vanessa Evans
is on an “as is”basis.The author and the publisher shall have neither liability
nor responsibility to any person or entity with respect to any loss or damages Book Designer
arising from the information contained in this book.
Gary Adair
Bulk Sales
Page Layout
Sams Publishing offers excellent discounts on this book when ordered Gloria Schurick
in quantity for bulk purchases or special sales.For more information,
please contact
U.S.Corporate and Government Sales
1-800-382-3419
[email protected]
For sales outside of the United States,please contact
International Sales
[email protected]
The Safari® Enabled icon on the cover of your favorite technology book means the book is
available through Safari Bookshelf.When you buy this book,you get free access to the online
edition for 45 days.Safari Bookshelf is an electronic reference library that lets you easily search
thousands of technical books,find code samples,download chapters,and access technical information
whenever and wherever you need it.
To gain 45-day Safari Enabled access to this book:
n Go to http://www.samspublishing.com/safarienabled
n Complete the brief registration form
n Enter the coupon code CPA9-NUSB-2JMG-ZYCT-DM8Q
If you have difficulty registering on Safari Bookshelf or accessing the online edition,please email
[email protected].
❖
This book was made possible by the endless devotion and
encouragement from my wife,Lisa,and the intoxicating
cheer and innocence of my children,Zoe and Gianna.
❖
Contents at a Glance
Introduction
1 Scaling Up (and Down) 5
2 Principles for Avoiding Failure 11
3 Mission-Critical Environments 25
4 High Availability.
HA! No Downtime?! 37
5 Load Balancing
and the Utter Confusion Surrounding It 61
6 Static Content Serving
for Speed and Glory 75
7 Static Meets Dynamic
Adding Caches to Reduce Costs 105
8 Distributed Databases Are Easy,Just Read the
Fine Print 137
9 Juggling Logs
and Other Circus Tricks 169
10 The Right Tool for the Job 199
A Spread 227
Index 247
Table of Contents
Introduction 1
1 Scaling Up (and Down) 5
Defining Scalability 5
Why Do We Need to Scale? 6
Scaling Up Gone Wrong 6
What Goes Up Should Go Down 7
Real-World Considerations 8
Being a Good Architect 9
2 Principles for Avoiding Failure 11
Working in Production Environments 12
The Dot Bomb and Its Effect on Building Large
Systems 13
Stability and Control 14
Rapid Development 15
Unit Testing 16
Version Control 18
Version Control in Action 20
A Different Approach to Disaster Recovery 22
Good Design 23
3 Mission-Critical Environments 25
High Availability 26
Monitoring 27
Monitoring Implementations 27
Criteria for a Capable Monitoring System 29
Coping with Release Cycles 30
Internal Release Cycles 31
External Release Cycles 33
The Cost of Complexity
Shackled to Large Architectures 34
Looking for Speed 34
It’s Not a One-Man Mission 36
viii Contents
4 High Availability.
HA! No Downtime?! 37
Why High Availability and Load Balancing Are
Different 41
Load Balancing Is Not High Availability 42
High Availability Is Not Load Balancing 42
Traditional High Availability—The Whitepaper
Approach 43
Surveying the Site 45
Pouring Concrete—Foundry ServerIron 45
High Availability Rethought (Peer-Based) 49
Peer-Based High Availability in the
Real World 52
Growing Seamlessly 55
Diverging from the Web:High Availability for Email,
DNS,and So On 55
Pouring Concrete 56
5 Load Balancing
and the Utter Confusion Surrounding It 61
Load Balancing Basics 61
IP-Friendly Services 63
Web Switches 65
IP Virtual Servers 67
Application Layer Load Balancers 67
A Real Use 69
Abusing the Term 71
The Web and Beyond 72
Session Stickiness:A Fatal Misconception 73
So,Which One Is the Best? 74
6 Static Content Serving
for Speed and Glory 75
What’s So Tricky? 76
Context Switching 77
Resource Utilization 78
The Goal 81
Building the Cluster 82
Setting Goals 83
Contents ix
Tackling Content Distribution 83
A Priori Placement 84
Cache-on-Demand 86
Choosing a Web Serving Platform 88
Examining Our Availability Requirements 90
Choosing an OS 90
Wackamole 91
Reasoning 91
Installation 91
Testing the High Availability 94
Serving Content 98
World Domination 99
DNS Round-Trip Times 101
Anycast—Shared IP 102
A Final Review 104
Was It Worth It? 104
7 Static Meets Dynamic
Adding Caches to Reduce Costs 105
Types of Caches 107
Layered/Transparent Cache 107
Integrated (Look-Aside) Cache 109
Data Cache 112
Write-Thru and Write-Back Caches 113
Distributed Cache 114
Deploying Caches 117
Serving a News Site 117
Simple Implementation 119
Introducing Integrated Caching 122
Tackling User Data 127
Two-Tier Execution 130
Caching Is Powerful 134
8 Distributed Databases Are Easy,Just Read
the Fine Print 137
What Is a Distributed Database? 137
Data Resiliency 137