Planning LoadRunner Implementation - LoadRunner

The next step is to decide how to use LoadRunner to achieve your testing goals.

Defining the Scope of Performance Measurements

You can use LoadRunner to measure response time at different points in the application. Determine where to run the Vusers and which Vusers to run according to the test objectives:

• Measuring end-to-end response time:
  You can measure the response time that a typical user experiences by running a GUI Vuser or RTE Vuser at the front end. GUI Vusers emulate real users by submitting input to and receiving output from the client application; RTE Vusers emulate real users submitting input to and receiving output from a character-based application. You can run GUI or RTE Vusers at the front end to measure the response time across the entire network, including a terminal emulator or GUI front end, network, and server.



• Measuring network and server response times: You can measure network and server response time, excluding response time of the GUI front end, by running Vusers (not GUI or RTE) on the client machine. Vusers emulate client calls to the server without the user interface. When you run many Vusers from the client machine, you can measure how the load affects network and server response time.



• Measuring GUI response time:
  You can determine how the client application interface affects response time by subtracting the previous two measurements:
  GUI response time = end-to-end - network and server



• Measuring server response time:
  You can measure the time it takes for the server to respond to a request without going across the network. When you run Vusers on a machine directly connected to the server, you can measure server performance.



• Measuring middleware-to-server response time:
  You can measure response time from the server to middleware if you have access to the middleware and its API. You can create Vusers with the middleware API and measure the middleware-server performance.

Defining Vuser Activities

Create Vuser scripts based on your analysis of Vuser types, their typical tasks and your test objectives. Since Vusers emulate the actions of a typical enduser, the Vuser scripts should include the typical end-user tasks. For example, to emulate an online banking client, you should create a Vuser script that performs typical banking tasks. You would browse the pages that you normally visit to transfer funds or check balances.

You decide which tasks to measure based on your test objectives and definetransactionsfor these tasks. Transactions measure the time that it takes for the server to respond to tasks submitted by Vusers (end-to-end time). For example, to check the response time of a bank Web server supplying an account balance, define a transaction for this task in the Vuser script. In addition, you can emulate peak activity by using rendezvouspointsin your script. Rendezvous points instruct multiple Vusers to perform tasks at exactly the same time. For example, you can define a rendezvous to emulate 70 users simultaneously updating account information.

Selecting Vusers

Before you decide on the hardware configuration to use for testing, determine the number and type of Vusers required. To decide how many Vusers and which types to run, look at the typical usage model, combined with the testing objectives. Some general guidelines are:

• Use one or a few GUI users to emulate each type of typical user connection.
• Use RTE Vusers to emulate terminal users.
• Run multiple non-GUI or non-RTE Vusers to generate the rest of the load for each user type. For example, suppose that you have five kinds of users, each performing a different business process:

Choosing Testing Hardware/Software

The hardware and software should be powerful and fast enough to emulate the required number of virtual users. To decide on the number of machines and correct configuration, consider the following:

• It is advisable to run the LoadRunner Controller on a separate machine.
• Each GUI Vuser requires a separate Windows-based machine; several GUI Vusers can run on a single UNIX machine.
• Configuration of the test machine for GUI Vusers should be as similar as possible to the actual user’s machine.

Refer to the following tables to estimate the required hardware for each LoadRunner testing component. These requirements are for optimal performance.

Windows Configuration Requirements

Note: The results file requires a few MB of disk space for a long scenario run with many transactions. The load generator machines also require a few MB of disk space for temporary files if there is no NFS.

UNIX Configuration Requirements

Note: The results file requires a few MB of disk space for a long scenario run with many transactions. The load generator machines also require a few MB of disk space for temporary files if there is no NFS.