Measuring capacity.
WHAT IT ESTABLISHES
How much load the service handles before degrading Where the limit is What fails first
WHAT TO TEST
Realistic paths, in realistic proportions.
WHY REALISTIC
Testing one cheap endpoint tells you nothing about actual capacity.
WHAT TO INCLUDE
Authentication Write operations, not only reads Realistic data volumes
WHAT TO MEASURE
Response time distribution at each load level Error rate Resource utilisation
WHAT TO LOOK FOR
The point where response times rise sharply.
WHAT THAT INDICATES
A resource reaching saturation.
WHAT TO IDENTIFY
Which resource: processor, memory, database connections, external service.
WHAT TO TEST AGAINST
An environment resembling production.
WHY
Results from a different configuration are not transferable.
WHAT TO BE CAREFUL WITH
Testing against production, which affects real users Testing external services, which may block you
WHAT TO DO ABOUT THAT SECOND POINT
Substitute them, or obtain permission.
WHAT TO REPEAT
The test, after significant changes.
