Combining Performance Testing and Modelling for easyjet.com

Transcription

1 Combining Performance Testing and Modelling for easyjet.com Danny Quilton, COO, Capacitas Agenda Business Context easyjet s Goals Challenges with Agile How can we Reduce Risk? Performance Testing Performance Modelling What you need Costs Benefits Capacitas

2 About Capacitas UK-based Capacity and Performance Management specialists Training and professional services Hardware-vendor independent Tools independent Capacitas Business Context Capacitas

3 Business Context Capacity planning service Business critical service 98% of revenue earned through the e-commerce service Highly competitive market Frequent innovation by adopting agile development Monthly software releases Legislative changes Consistent growth; typically 20% p.a. Low-cost operating model Requirement to manage risk Capacitas easyjet s Goals Capacitas

4 easyjet s Goals Capacitas Agile Development Process Product Backlog Scrum (Daily Meeting) OUT Sprint Planning Meeting IN Sprint Backlog Sprint (15-30 days) Sprint Review Pre-release Activities (e.g. Training, Documentation) LESSONS LEARNED Sprint Retrospective Meeting Release Capacitas

5 Challenges Associated with Agile Frequent change introduces risk Window available for performance testing is typically 1-2 weeks Final production candidate code often not available at the start of testing Multiple code releases within the testing window Increased probability of functional and environmental defects Frequent rework of code necessitates modifications to test scripts Cumulative effect on capacity from 12 releases per annum Narrow time window to resolve performance defects Capacitas Challenges Associated with Agile Capacitas

6 Typical Causes of Degraded Service Performance Capacitas Cause of degraded performance How Can We Reduce Risk? Mitigated by performance testing? Changes in user patterns No Yes Poor performance of 3 rd parties Physical capacity bottlenecks May be limited by environment May be limited by size of the environment Logical bottlenecks Yes If known Mitigated by modelling? Software configuration changes Yes Yes, if tested Yes Yes Increases in demand May be limited by size of the environment Yes Capacitas

7 Why Test? Performance testing is used to understand the software s performance characteristics Do unknown time and growth related defects exist? Memory leaks Poor database design/indexing Do unknown concurrency related defects exist? Database locking issues Memory locking issues Race conditions Obtain model inputs Capacitas Why Model? Modelling uses our understanding of the software to predict end to end service performance under different scenarios Capacitas

8 Scenario Modelling Capacitas Coverage of Testing and Modelling Testing Modelling Application Infrastructure Business Scenarios Technical Scenarios Capacitas

9 High Level Process Capacitas Risk Assessment Capacitas

10 Risk Assessment Assess the potential performance impact on different elements of infrastructure Plan tests to help mitigate that impact Focus on areas of highest risk due to limited timeframes Description ID Web Risks DB Other Risk Mitigation Project X --- Medium Medium Low Test 1 Project Y --- Low High Medium Tests 2 & 3 Project Z --- Low Low Low None Capacitas Performance Tests Employed Capacitas

11 Baseline Tests Used to determine the impact of the planned release Comparative performance between releases May be Load, Stress or Soak Tests Service times and response times are compared to each other Example service time comparison between two fictional baseline tests Service Time (ms) Database Server Service Time Web Server Service Time Test 1.1 Release X Test 1.1 Release Y % Difference 8% -4% Capacitas Single Transaction Type Tests To determine the impact on the infrastructure of individual user transactions Every business process which is to be modelled will have a calculated service time for each hardware element Milliseconds Web CPU per page (fictional data) Home Search Select Options Login Purchase Capacitas

12 Modelling Performance Test Results Capacitas Performance Modelling Business Service Component Virtual Infrastructure Capacitas

13 Performance Modelling Aircraft Business Home Page Search Booking Service HTTP1 APP1 APP2 DB1 Component Virtual Infrastructure Capacitas Performance Modelling 600 Business Service Component Virtual Infrastructure 3.5 transactions/s Capacitas

14 Model Scope What infrastructure to include? Major contributor to the performance experienced by end-user Highly utilised Critical Load growth Frequently reviewed Virtual Infrastructure Capacitas Model Scope What transactions to include Business critical Importance to revenue High-volume High component cost Home Page Search Booking Change Password Service Capacitas

15 Demand Model Validation The model should be validated on an ongoing basis against actual values The first stage is to validate the demand part of the model to ensure that arrival rates are being calculated correctly Following this the true demand can be used to validate the utilisation calculations Capacitas Capacity and Performance Model Validation 100% Comparison of Actual Database Load to Predicted Database Load 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% Actual Database CPU Predicted Database CPU Capacitas

16 What you need People Capacity and performance management skills: Demand forecasting Modelling Load testing A strong understanding of risk management A good understanding of the business model Flexibility Project management skills Capacitas What you need Process Interface with the release team Participation in the agile development scrums Access to developers to understand application functionality Interface with the test environment management team for test planning Interface to the business to access business forecasts Interface to operations to access production measurements Capacitas

17 What you need Tools & Environment An appropriately sized test environment Production-like environment is not required Consider the ratio of capacity between presentation, business and data tiers Toolset Performance monitoring tools (production and test) Load generation tool Modelling tool Capacitas What you need Environment Capacitas

18 What you need Data Software/hardware configuration (production and test) Performance measurements from production and test environments Benchmark data (Spec, TPC, etc.) Service times derived from performance test results SLAs Internal SLAs with third-parties Historical and forecast business demand Historical and forecast service demand Measured error of previous forecasts Capacitas Historical Business Demand Fleet Plan to April 2009 y = x R² = Number of Owned Aircraft GB Airways acquisition Mar-04 Jun-04 Sep-04 Dec-04 Mar-05 Jun-05 Sep-05 Dec-05 Mar-06 Jun-06 Sep-06 Dec-06 Delivery Date Mar-07 Jun-07 Sep-07 Dec-07 Mar-08 Jun-08 Sep-08 Dec-08 Mar-09 Capacitas

19 Historical Service Demand Capacitas Costs Capacitas

20 Benefits Capacitas give us the confidence in making the correct release decision James Mackay, Test Manager, easyjet Test Phase Risk Assessment Performance Test Plan Targeted Performance and Stress Testing Regression Performance and Stress Testing All Defects: Closed Capacity Models Updated Status Complete Complete Complete Complete Complete Complete Capacity Plan updated and communicated Complete Capacitas Benefits Testing and modelling complement one another The combined approach provides effective risk-mitigation in the context of: Frequent change Narrow performance test window Business growth The approach enables us to rapidly answer business and technical what if scenarios Costs are limited through the use of a scaled-down performance test environment and low-cost modelling tools Provides performance assurance in a highly competitive market place Capacitas

21 Questions? Presentation will be available for download at Please visit us at our stand for any further questions Capacitas