A Handbook for Load Testing

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result in instantly identifying the performance bottle necks during load testing. But if the tools sup-port real time monitoring then testers would be able to view the application per-formance at any time during the test.

Thus running the load test scenario and monitoring the performance would accel-erate the test process thereby producing a more stable application

Analyzing Results
The last but most important step in load testing is collecting and processing the data to resolve performance bottlenecks. The reports generated can be anything ranging from Number of hits, number of test clients, requests per second, socket errors etc.,

Hence analyzing the results will isolate bottle necks and determine which changes are needed to improve the system performance. After these changes are made the tests must re run the load test scenarios to verify adjustments.

Load Testing with WAST
Web Application Stress is a tool to simulate large number of users with a relatively small number of client machines. Performance data on an web application can be gathered by stressing the website and measuring the maximum requests per second that the web server can handle. The next step is to determine which re-source prevents the requests per second from going higher, such as CPU, memory, or backend dependencies. This section will give the basics and most easiest way of performing load testing using WAST.

Creating a Test Script
You can create test scripts using Web Application stress for load testing of your web application in the following ways,

  • Manually
  • By recording with a browser
  • From an IIS log
  • From the web site content

For ease let us discuss how can Test scripts can be created by recording with a browser.

The first step involved would be to create a database which will hold your scripts i.e., you need to create a web application stress database. This database will con-tain all the scripts that are generated as a result of your recording on various actions that were performed on the web application. It would be advisable to create a separate database for separate projects.

Once a database is created remove the sample script provided by the default. You can create one!! Choose the menu options to create a script by recording. This would prompt the user to choose the following

  • Record delay between records
  • Record browser cookies
  • Record the host header

User can select anything depending upon their needs. Once this is finished the user will be prompted to enter the web address in the address bar of the browser. The user should enter the URL for the web application which is under test. Stop recording after finishing all your actions. Once recording is stopped the user will be able to see the details of the pages that the user has browsed.

Now you can change your settings to configure how the WAST should stress you application. Web Application Stress allows you to specify the Stress level (threads) and Stress multiplier (sockets per thread) for greater control of a test run. Stress level is the total number of Windows NT threads that are created across all of the clients. Each thread can create multiple sockets and each socket is a concurrent request. The following formula explains this relationship:

Total Concurrent Requests = Stress level x Stress multiplier = Total Number Sockets

The test run time can be varied depending upon how much time the script needs to be run. For example giving the test run time as 1 minute would run the script for a minute and would stop the execution of the scripts.

Once the test is run with the

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