Preparing For The Flood. How Do You Conduct Load Testing To Ready Your WordPress Site For Viral Events?
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The document provides a comprehensive guide on how to load test a WordPress site to prepare for potential viral events that could lead to increased traffic. It outlines the importance of load testing, discusses different types of scenarios, and provides tools and methods for executing effective tests. Key considerations include preparing realistic testing scenarios, determining KPIs, and analyzing server performance under load.
Preparing For The Flood. How Do You Conduct Load Testing To Ready Your WordPress Site For Viral Events?
- 1. Preparing for the Flood How to Load Test to Prepare your WordPress site for a viral event.
- 2. Who is this idiot? My name is Robert Li. I’m a Solutions Engineer for WP Engine. I’ve founded 3 startups and exited 1. I have a 3 year old teacup pomeranian named Chelsey. I am a long suffering Knicks fan. I love making WordPress do weird, wonderful things.
- 3. Takeaways 1. Solutions 2. Why Load Test? 3. What do you need? 4. (Pray to the Demo Gods) 5. Demo 6. How do you prepare? 7. Let’s take a look Degree of Difficulty: Nerd
- 9. The problem Your Site You’ve created a site with lots of cool features, that has a great user experience, and that you’ve spend tonne’s of money (or time) on. Your Hosting You’ve signed up to some hosting that will fit your new site, in its current state. It works great! The Flood You send a shirt to an influencer, they wear it, you actually start selling stuff, which is great! Then your site goes down. WHAT HAPPENED...
- 11. So how many cars can I actually fit?
- 12. Solution Let’s do some load testing!
- 13. Why Load Test?
- 14. Functional Tests don’t reflect the Real World Testing the functionality of your site or application doesn’t reflect how users will use it in real life. They may run across bottlenecks in complex situations your testing can’t account for.
- 15. Your code can behave differently under load Any changes to code to an established website can cause it to behave differently under load. Bugs can appear that you didn’t detect in other testing.
- 16. Servers perform differently under stress When scaling to 100s, 1000s or potentially Millions of concurrent users, you may get completely different results for CPU load, error rate, I/O throughput, and response times. Houston we have a problem
- 17. The cost of failure is extremely high. 50% of users will leave if a page takes longer than 6.5s to load. 1 minute of downtime during Black Friday costs US$4700 on average. Downtime during a peak traffic event damages brand integrity and creates a snowball effect. https://royal.pingdom.com/page-load-time-really-affect-bounce-rate/ https://www.blazemeter.com/blog/why-load-testing-is-important/
- 18. What do you need?
- 19. Execution How do you execute a load test? Reaction How does the server react to the load test?
- 20. Load Testing Terms Primer Scenarios - A template or script of what a user might do on a site. Virtual Users/User Agents - Simulated users Concurrency - How many actions and users are happening and on the site at any given time 504, 502, 429 errors - When the server is either crapping itself, or protecting itself from “crapping itself”. .yaml - The file format that holds scenarios
- 21. Execution Ingredients: Servings: 1000vu ● Taurus - Open source, creates the Virtual Users that perform scenarios. ● Blazemeter - Visualizes the data (can also execute load tests) ● jMeter - Software to help you build and tweak scenarios ● Blazemeter Chrome Extension - Records your actions on a website to start as the basis for a scenario
- 22. Reaction Ingredients: Servings: 1 overloaded server htop sar -q 1 ● Stackdriver/Cloudwatch - Server monitoring (GCP/AWS). OpenNMS is agnostic & open source. ● New Relic - Monitoring the application (WordPress) itself. ● Pingdom/Uptime Robot/freshping - Measures whether the website is up. ● htop/sar -q 1 - Command Line (CLI) Live monitoring.
- 23. CAVEATS DO NOT LOAD TEST… ❏ On your production environment ❏ On a shared environment ❏ Without telling your host’s support/security team ❏ On a site or web application you don’t have permission to blast. x x x x
- 24. LET’S START
- 28. How do you prepare?
- 29. Do as much as possible before testing Decide what to complete and what to defer. Bottlenecks found in functional testing? Optimize to get a true to life response.
- 30. Deciding Test Type Spike - How does a system respond to a sudden increase and decrease in load? e.g. A Live Online Event Stress - How does a system respond to consistent high intensity loads? Where does it fail? How does it recover? e.g. A Flash Sale Soak - How does a system respond to high load over time? e.g. Black Friday
- 31. Creating Realistic Scenarios Start with the user journey Your marketing and web team are integral to generating realistic test scenarios. Have them map out ~5 user profiles and journeys. Usually this is their funnel ● From where and how do users access the site? ● What do they do on the site? ● How do they arrive? In waves? ● How long do they stay?
- 32. Determine your KPIs What is acceptable? Not what is ideal. What level of existence are you willing to accept? Considerations: ● Response Time ● Error % ● Ratio of failed to successful transactions ● Maximum requests per second ● Apdex Score
- 33. Start small before scaling up big... Do small scale testing to discover errors and bottlenecks in your own scenarios and with your own tech stack. Common Questions to ask yourself: ● Is the script broken? ● Is it calling on a resource that doesn’t exist or performing an impossible action? ● Is the testing platform actually the bottleneck? ● Are there optimizations I can make to improve headroom?
- 34. What is the tipping point? When does acceptable become unacceptable?
- 35. Under load is 80% usage Test for 120% usage When number of hits/s plateaus this indicates: ● System can no longer support extra concurrent requests ● You are at max concurrent users.
- 36. LET’S TAKE A LOOK
- 38. WHAT DO YOU DO NOW? Analyze > Tune > Retest > Rinse and Repeat
- 40. Questions? Robert Li E: [email protected] P: +61-(0)-7-5613-1084 SM: LinkedIn (Look Left!) https://www.linkedin.com/in/robert-li Download: https://dsh.re/896ac