Analyze the application

This section describes how to analyze the application under test as part of the load test planning process.

Identify system components

Draw a schematic diagram to illustrate the structure of the application. If possible, extract a schematic diagram from existing documentation. If the application under test is part of a larger network system, you should identify the component of the system to be tested. Make sure the diagram includes all system components, such as client machines, network, middleware, and servers.

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Describe the system configuration

Enhance the schematic diagram with more details. Describe each system component's configuration. You should be able to answer the following questions:

  • How many users are anticipated to connect to the system?

  • What is the application client's machine configuration (for example: hardware, memory, operating system, software, development tool)?

  • What types of database and web servers are used (for example: hardware, database type, operating system, file server)?

  • How does the server communicate with the application client?

  • What is the middleware configuration and application server between the front-end client and back-end server?

  • What other network components may affect response time (such as modems)?

  • What is the throughput of the communications devices? How many concurrent users can each device handle?

Example: The schematic diagram of the online banking system specified that there are multiple application clients accessing the system.

Front-End Client Configuration
Anticipated number of application clients
50 concurrent application clients
Hardware / Memory
Intel Core i7-4930K @ 3.40GHz
Operating system & version
Windows Server 2019 64-bit
Client browser
Microsoft Edge

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Analyze the usage mode

Define how the system is typically used and decide which functions are important to test. Consider who uses the system, the number of each type of user, and each user's common tasks. In addition, consider any background load that might affect the system response time.

Example: Suppose 200 employees log on to the accounting system every morning, and the same office network has a constant background load of 50 users performing various word processing and printing tasks. You could create a scenario with 200 virtual users signing in to the accounting database, and check the server response time.

To check how background load affects the response time, you could run your scenario on a network where you also simulate the load of employees performing word processing and printing activities.

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Examine task distribution

In addition to defining the common user tasks, examine the distribution of these tasks.

Example: Suppose the bank uses a central database to serve clients across many states and time zones. The 250 application clients are located in two different time zones, all connecting to the same web server. There are 150 in Chicago and 100 in Detroit. Each begins their business day at 9:00 AM, but since they are in different time zones, there should never be more than 150 users signing in at any given time. You can analyze task distribution to determine when there is peak database activity, and which activities typically occur during peak load time.

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