Scalability Testing

Scalability testing is a type of performance testing that evaluates how a system handles increases in workload. The goal is to determine at what point a system stops functioning or degrades in performance as load increases. Key terms include load testing and stress testing.

Scalability testing focuses on gradually ramping up the workload on a system until it reaches a breaking point. For example, a scalability test might start with 100 concurrent users accessing a web application. Load would then steadily increase to 500, 1000, 5000 users and so on. At each level, response times, throughput, and error rates are measured. The test identifies the maximum workload the system can handle while still meeting performance thresholds. Common bottlenecks like database connection limits or memory utilization may be uncovered. Stress testing takes this further by spiking system load to extreme levels to find the actual breaking point. Together, these tests help set scalability requirements and ensure systems can handle projected growth in users or transactions.

Scalability testing is an important technique for validating that systems are designed to scale up properly. It provides confidence that architecture and infrastructure will continue performing well under high demand. The data also aids in capacity planning and identifying potential scaling pain points before they impact customers.