Configure for high-scale load testing

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  • 2 minutes to read

In this article, learn how to set up a load test for high-scale load with Azure Load Testing Preview. To simulate a large number of virtual users, you'll configure the test engine instances.

Important

Azure Load Testing is currently in PREVIEW. See the Supplemental Terms of Use for Microsoft Azure Previews for legal terms that apply to Azure features that are in beta, preview, or otherwise not yet released into general availability.

Prerequisites

  • An Azure account with an active subscription. If you don't have an Azure subscription, create a free account before you begin.

  • An existing Azure Load Testing resource. To create an Azure Load Testing resource, see the quickstart Create and run a load test.

Requests per second (RPS)

The maximum number of requests per second (RPS) that Azure Load Testing can generate depends on the application's latency and the number of virtual users (VU).

You can apply the following formula: RPS = (# of VUs) * (1/latency).

For example, if application latency is 20 ms, and you're generating a 2000 VUs load, you can achieve around 100,000 RPS.

Test engine instances

In Azure Load Testing, test engine instances are responsible for executing the test plan. If you used an Apache JMeter script to create the test plan, each test engine executes the Apache JMeter script.

The test engine instances run in parallel. They allow you to define how you want to scale out the load test execution for your application.

In the Apache JMeter script, you define the number of parallel threads. This number indicates how many threads each test engine instance executes in parallel. Each thread represents a virtual user. The recommendation is to keep the number of threads below a maximum of 250.

For example, to simulate 1000 threads (or virtual users), set the number of threads in the Apache JMeter script to 250. Then configure the test with four test engine instances (4 x 250 threads).

Important

For public preview, we support up to 45 engine instances for a test run.

Configure your test plan

In this section, you'll configure the scaling settings of your load test.

  1. Sign in to the Azure portal by using the credentials for your Azure subscription.

  2. Navigate to your Load Testing resource, and select Tests from the left navigation to view the list of tests. Next, select the test from the list by checking the box, and then select Edit.

    Screenshot that shows the list of tests.

  3. You can also modify the test configuration from the test details page. Select Configure, and then Test to edit the test.

    Screenshot that shows how to configure a test from the test details page.

  4. In the Edit test page, navigate to the Load tab and configure the Engine instances input field.

    Screenshot that shows the Load tab when editing a test.

  5. Select Apply to modify the test and use the new configuration when you rerun the test.

Next steps