Configure a load test for high-scale load testing
In this article, learn how to set up a load test for high-scale load by using 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. For legal terms that apply to Azure features that are in beta, in preview, or otherwise not yet released into general availability, see the Supplemental Terms of Use for Microsoft Azure Previews.
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.
Determine requests per second
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 (VUs).
You can apply the following formula: RPS = (# of VUs) * (1/latency).
For example, if application latency is 20 milliseconds (ms), and you're generating a load of 2,000 VUs, you can achieve around 100,000 RPS.
Test engine instances
In Azure Load Testing, test engine instances are responsible for executing a test plan. If you use 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. We recommend that you keep the number of threads below a maximum of 250.
For example, to simulate 1,000 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 (that is, 4 x 250 threads).
Important
For preview release, Azure Load Testing supports up to 45 engine instances for a test run.
Configure your test plan
In this section, you configure the scaling settings of your load test.
Sign in to the Azure portal by using the credentials for your Azure subscription.
Go to your Load Testing resource. On the left pane, select Tests to view the list of load tests.
In the list, select your load test, and then select Edit.
You can also edit the test configuration from the test details page. To do so, select Configure, and then select Test.
On the Edit test page, select the Load tab. In the Engine instances box, enter the number of test engines required to run your test.
Select Apply to modify the test and use the new configuration when you rerun it.
Next steps
For more information about comparing test results, see Compare multiple test results.
To learn about performance test automation, see Configure automated performance testing.