There are 3 primary functions that you need to consider when load testing your web application:

  1. Build a test plan – define the traffic behavior
  2. Run a test – define how much, duration, schedule
  3. Analyze the test results – view the reports

LoadStorm’s user interface presents each of these to you by clicking on a tab at the top of the page.

Build a Test Plan

A test plan is what tells LoadStorm the VUser activities to simulate. When you run a load test, you must choose one of your plans.

This plan is defined by scenarios which represent different user types such as shoppers or administrators. Many people call a test scenario a test script. A scenario is built of steps. Each step hits a page or submits a form.

A plan contains scenarios, and scenarios contain steps, and steps contain requests (HTTP GET or POST).

An example test plan called “My E-commerce Traffic”:

  • Scenario #1 has steps defined for VUsers to put products into a shopping cart and pay with a credit card.
  • Scenario #2 has steps defined for VUsers to anonymously browse a product catalog.
  • Scenario #3 has steps defined for VUsers to login and post their opinions about your products.
  • Scenario #4 has steps defined for VUsers to randomly click around on your site.

The plan also allocates a percentage of all VUsers in a test to each of the scenarios. It is common to have fewer buyers than “window shoppers”, so you can control that only 20% of VUsers complete a purchase, for example.

Run a Load Test

Execution of a test plan generates requests against your target web server. LoadStorm will execute the steps in each scenario with the specified number of virtual users in the timeframe allotted. The load generators are dynamically spawned by the LoadStorm Scheduler to accommodate the requested increases in volume.

Running a load test involves choosing the plan, setting the timing/duration, and defining the number of users to simulate. The screenshot below shows all of the necessary form fields that need to be completed to run a test.

You control these key settings for a test:

  • Plan – choose the test plan and scenarios that define the traffic behaviors.
  • When – run the test ASAP or schedule for the future.
  • Pattern – linear for smooth ramp up or step-up for waves of increase in VUsers.
  • Start Users – beginning volume should be small enough to not overwhelm the server.
  • Peak Users – the maximum VUsers reached for last 10% of test duration.
  • Step Time – how frequently to increase VUsers (only for step-up pattern).
  • Step Increase – how many VUsers to increase (only for step-up pattern).

The performance metrics will appear on two graphs while the test is running. Each metric is plotted in one-minute intervals.

Run a Load Test – Video Tutorial

Analyze Test Results

LoadStorm maintains the data for each load test that has been run in your account.

After the test is finished running, you can revisit any of your tests to dig a little deeper by going to the Analyze tab. There is a list of all your load tests. Click on the Details button to see the graphs and links to reports. Additionally, you can download a CSV file that contains every request and response that occurred during your test.

Currently, LoadStorm tracks the following metrics:

  • Concurrent users
  • Requests per second
  • Average response time
  • Error rate percentage
  • Throughput in kilobytes per second
  • Peak response time
  • Pages by error code
  • Pages by response time

For a detailed explanation, please see our page on load testing metrics.

Watch a video tutorial on test results graphs and reports

Analyzing test results where the system under test fails

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