Preface xv Acknowledgments xxi About the Authors xxiii Chapter 1: Reduce the Equation 1 Rule 1-Don't Overengineer the Solution 3 Rule 2-Design Scale into the Solution (D-I-D Process) 6 Rule 3-Simplify the Solution Three Times Over 8 Rule 4-Reduce DNS Lookups 10 Rule 5-Reduce Objects Where Possible 12 Rule 6-Use Homogeneous Networks 15 Summary 15 Notes 16 Chapter 2: Distribute Your Work 19 Rule 7-Design to Clone or Replicate Things (X Axis) 22 Rule 8-Design to Split Different Things (Y Axis) 24 Rule 9-Design to Split Similar Things (Z Axis) 26 Summary 28 Notes 28 Chapter 3: Design to Scale Out Horizontally 29 Rule 10-Design Your Solution to Scale Out, Not Just Up 31 Rule 11-Use Commodity Systems (Goldfish Not Thoroughbreds) 33 Rule 12-Scale Out Your Hosting Solution 35 Rule 13-Design to Leverage the Cloud 40 Summary 42 Notes 42 Chapter 4: Use the Right Tools 43 Rule 14-Use Databases Appropriately 47 Rule 15-Firewalls, Firewalls Everywhere! 52 Rule 16-Actively Use Log Files 55 Summary 58 Notes 58 Chapter 5: Get Out of Your Own Way 59 Rule 17-Don't Check Your Work 61 Rule 18-Stop Redirecting Traffic 64 Rule 19-Relax Temporal Constraints 68 Summary 70 Notes 70 Chapter 6: Use Caching Aggressively 73 Rule 20-Leverage Content Delivery Networks 75 Rule 21-Use Expires Headers 77 Rule 22-Cache Ajax Calls 80 Rule 23-Leverage Page Caches 84 Rule 24-Utilize Application Caches 86 Rule 25-Make Use of Object Caches 88 Rule 26-Put Object Caches on Their Own "Tier" 90 Summary 91 Notes 92 Chapter 7: Learn from Your Mistakes 93 Rule 27-Learn Aggressively 95 Rule 28-Don't Rely on QA to Find Mistakes 100 Rule 29-Failing to Design for Rollback Is Designing for Failure 102 Summary 105 Notes 106 Chapter 8: Database Rules 107 Rule 30-Remove Business Intelligence from Transaction Processing 109 Rule 31-Be Aware of Costly Relationships 111 Rule 32-Use the Right Type of Database Lock 114 Rule 33-Pass on Using Multiphase Commits 116 Rule 34-Try Not to Use Select for Update 118 Rule 35-Don't Select Everything 120 Summary 121 Notes 122 Chapter 9: Design for Fault Tolerance and Graceful Failure 123 Rule 36-Design Using Fault-Isolative "Swim Lanes" 124 Rule 37-Never Trust Single Points of Failure 130 Rule 38-Avoid Putting Systems in Series 132 Rule 39-Ensure That You Can Wire On and Off Features 135 Summary 138 Chapter 10: Avoid or Distribute State 139 Rule 40-Strive for Statelessness 140 Rule 41-Maintain Sessions in the Browser When Possible 142 Rule 42-Make Use of a Distributed Cache for States 144 Summary 146 Notes 146 Chapter 11: Asynchronous Communication and Message Buses 147 Rule 43-Communicate Asynchronously as Much as Possible 149 Rule 44-Ensure That Your Message Bus Can Scale 151 Rule 45-Avoid Overcrowding Your Message Bus 154 Summary 157 Chapter 12: Miscellaneous Rules 159 Rule 46-Be Wary of Scaling through Third Parties 161 Rule 47-Purge, Archive, and Cost-Justify Storage 163 Rule 48-Partition Inductive, Deductive, Batch, and User Interaction (OLTP) Workloads 166 Rule 49-Design Your Application to Be Monitored 169 Rule 50-Be Competent 172 Summary 174 Notes 174 Chapter 13: Rule Review and Prioritization 177 A Risk-Benefit Model for Evaluating Scalability Projects and Initiatives 177 50 Scalability Rules in Brief 180 A Benefit/Priority Ranking of the Scalability Rules 200 Summary 202 Index 205