what is the best approach to run performance test for scaled down environment?

Question

I have a task for load testing on application by 1,000 concurrent users. we are allowed to run load test on pre-prod environment which have 25% from production environment

what is the correct approach?

1. Run by 250 concurrent users on pre-prod environment and consider the response time of requests on production is equal to pre-prod environment. (ex. Run 250 users pre-prod Response= 1secs. >> Expect >> production Response = 1 secs with 1000 users)

2. Run by 1000 concurrent users on pre-prod environment and consider the response time of requests on pre-prod is 4 times of production environment. (ex. Run 1000 users pre-prod Response= 4secs. >> Expect >> production Response = 1 sec with 1000 users)

3. Run by 250 concurrent users on pre-prod environment and consider the response time of requests on production is 4 times of pre-prod environment. (ex. Run 250 users pre-prod Response= 1 secs. >> Expect >> production Response = 4 sec with 1000 users)

Answer 1

You cannot extrapolate the results you get for the scaled down environment to the full-size environment, if the scaled down environment has 25% of the production's hardware capacity it doesn't necessarily mean that you will get 4x times better results if you run the same test on production.

You can test:

1. Code and Database Interaction
2. External Service Calls
3. Load Allocation
4. Monitoring the Application Server
5. Run a Soak Test
6. Run a regression test once you have performance baseline is measured

More information: Performance Testing in a Scaled Down Environment. Part Two: 5 Things You Can Test