Load Testing

Most field problems for large-scale systems are rarely functional, instead they are load-related. Load Testing attempts to mimic multiple users repeatedly performing the same tasks, take hours or even days.

Designing a Load Test

Designing Realistic Loads Designing Fault- Inducing Loads Load Design Optimizations and Reductions

Characterizing an Aggregate Workload

• Workload Mix
  • browsing (30%), purchasing (10%) and searching (60%)
• Workload Intensity
  • Rate of requests (5 requests/sec)
• Steady Load
  • Ease of measurement – Memory leaks?
• Step-wise Load
  • Same workload mix
  • Different workload intensity

Markov Chains

We can use log files to determine a probabilistic model of our system. The model, Markov Chains, shows us how users transition between different pages. Once we have this model, we can use it to test the load on our system.