Performance testing using the OpenSTA Commander

Using the Commander you can define tests; each test can consist of one or more task groups, which are sequences of test scripts. Each task group has to contain at least one script. Once a script has been associated with a task group, it is called a task.

Test execution settings like the number of iterations or the number of virtual users (VU) can be specified per task group, while the number of iterations per task is also configurable. This modular structure makes the scenario easy to accomplish, where a user logs in first, then uses the Trade3 application a configurable number of times, and finally logs out (see Example 19-2).

Example 19-2 A exemplary modular test design in OpenSTA

Test Trade3 will be repeated 10 times, consisting of:
|
|--Task group Trade3.1: 50 VU
	|--Task-1: T3_Login, repeat count: 1
	|--Task-2: T3_Scenario-1, repeat count: 500
	|--Task-3: T3_Scenario-2, repeat count: 250
	|--Task-4: T3_Logout, repeat count: 1

To run a performance test using OpenSTA perform these steps:

1. Create the test

2. Specify runtime parameters

3. Execute the test

4. View the results

 

Create a test

The first step is to create a new test and add the previously recorded script:

1. In the Commander window, select File -> New Test -> Tests and enter Trade3 as the name of the new test.

2. Drag the script Trade3Scenario from the repository view on the left side onto the Task1 column on the right side of the Commander window. This creates a new task group called Trade3.1.

 

Specify runtime parameters

The next step is to configure the number of iterations for the task and the number of virtual users that will concurrently perform the scripted task. In this example, we will use 40 virtual users performing 10 iterations of the Trade3Scenario task.

1. Click Trade3Scenario in column Task1. Change the value in the Number of times each user will run this task (iterations) field to 10.

2. Click the field containing 1 in column VUs. Enter 40 for the Total number of virtual users for this task group.

 

Additional OpenSTA Commander features

Collectors, which gather operating system performance data like CPU utilization, network and disk I/O, etc., can be defined in the OpenSTA Commander. These collectors will gather data during the test execution and can then be correlated with the actual test results. The two supported collector schemes to gather data from are: Performance data available from the Windows System Monitor (Windows Management Instrumentation WMI) Simple Network Management Protocol (SNMP) data from SNMP enabled hosts or devices

 

Execute a test

The final step is to start the test using the OpenSTA Commander; while it is executing, the test's progress and statistics can be viewed. First you have to change the monitoring interval to five seconds. That way the statistics will be updated every five seconds (in a real world scenario the monitoring interval should be set even higher as to not influence the performance test by wasting CPU and network resources used for collecting performance data).

1. Set the monitoring interval to five seconds:
a. Select the Monitoring tab.
b. Click the Tools symbol.
c. Set both Task Monitoring Interval and Sampling Frequency to 5.

2. To start the test select Test -> Execute Test or press the green Play icon on the toolbar. During the test you can watch the progress and test statistics: a. Switch to the monitoring view by selecting the Monitoring register. b. Enable the Summary checkbox on the right side of the Commander window to see the following current statistics:
Active virtual users
Test duration
HTTP requests/second
Number of successful/failed HTTP requests

Right-click inside the Summary window to select and deselect additional statistics data.

The test will stop automatically after all 40 VUs have cycled through their 10 iterations of the Trade3Scenario task.

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