Stress testing should ideally be carried out under a:

Stress testing is designed to evaluate a system’s performance under extreme conditions1. It is typically carried out in a test environment that closely mirrors the production environment, using production workloads1. This approach ensures that the test results accurately reflect how the system would perform under similar conditions in the production environment1. Using a test environment also prevents any disruptions or damage to the production environment during testing1.

References:

Stress Testing Best Practices: A Seven Steps Model