Relation between maxVusers limit and requests

[chiralcentre]

Can I check why setting limit on maxVusers does not affect the total number of requests made throughout the testing phase? For the following file, regardless of whether the maxVusers limit is set, the total number of requests made is 30. On a related note, can I check if the number of requests made per second is equivalent to the arrivalRate?

config:
  target: <TARGET>
  phases:
    - duration: 30
      arrivalRate: 1
      name: Warm up phase
      maxVusers: 3
  plugins:
    apdex: {}
    metrics-by-endpoint: {}
  apdex:
    threshold: 100
scenarios:
  - flow:
    - get:
        url: <URL>
        timeout: 30000

[InesNi]

Hi @chiralcentre,

maxVusers represents max num of concurrent VU's at any given time, and arrivalRate VU's generated each second. Here are some examples.

[chiralcentre]

can I check if the virtual users persist after creation or do they send one requests each after generation and terminate?

[InesNi]

Hi @chiralcentre ,

You can find more about Artillery and how it works in the docs. Virtual users are explained here in core concepts

[hassy]

@chiralcentre Each VU runs the scenario (or one of the scenarios if you defined more than one) and terminates. The number of requests a VU will make depends on the scenario definition, i.e. whether a scenario only makes one request or multiple requests. The easiest way to reason about it is to imagine real users arriving to your app - a VU is created by Artillery, it runs a sequence of requests based on the scenario you define, and then they go away.

[hassy]

can I check if the number of requests made per second is equivalent to the arrivalRate?

They are not equivalent because a single VU can make multiple requests, and time between requests depends on the response time from the app (i.e. there's no constant rate of requests). This blog post might help understand Artillery's workload model a bit better: https://www.artillery.io/blog/load-testing-workload-models

[chiralcentre]

@hassy thank you for the clear response! I understand virtual users better now