LoadRunner Tutorial

7

Creating a Load Testing Scenario

In the previous lesson you successfully validated your test in the Virtual

User Generator.In this lesson, you will test your application under load. You

will emulate the actions of ten travel agents concurrently using the flight

reservation system, and observe the behavior of the system under load. To

design and run this test, you use the LoadRunner Controller.

In this lesson you will cover the following topics:

➤Introducing the LoadRunner Controller

➤What mixture of users should be part of the load test?

➤The Controller Window at a Glance

➤How do I generate a heavy load?

➤How do I emulate real load behavior?

➤How do I emulate different types of users?

➤How do I monitor the system under load?

Introducing the LoadRunner Controller

Load testing means testing your application under typical working

conditions, for example, many travel agents reserving flights on the same

flight reservation system at the same time.

You design the test to emulate real-life situations. To do this, you need to be

able to generate heavy load on an application and schedule when the load is

applied (since users do not log on and off the system at precisely the same

time). You also need to emulate different kinds of user activity and behavior.

For example, some users might be using Netscape instead of Internet

Explorer to see the application’s performance, and using different network

connections such as modem, DSL, or cable. You create and save these

settings in a scenario.

The Controller provides you with all the tools you need to help you build

and run tests to accurately emulate your working environment.

Scenario Objectives

In this lesson, the objective is to create a scenario that emulates the

behavior of ten travel agents simultaneously logging on, searching flights,

purchasing flights, checking itineraries, and logging off the system.

Starting the Controller

To begin creating a scenario, you open the Controller and create a new

scenario.

1 Open HP LoadRunner.

Choose Start > Programs >LoadRunner>LoadRunner. The HP LoadRunner

Launcher window opens.

What mixture of users should be part of the load test?

In this tutorial, you will use just one Vuser script to model a single group of

users performing identical actions. To emulate a real scenario with a more

varied mix of user profiles, you would create different groups running

several scripts with different user settings.

The script that you previously recorded in VuGen contains the business

processes that you want to test. They include logging on, searching for a

flight, buying a ticket, checking the flight itinerary, and then logging off the

site. You will add a similar script to the scenario, and configure the scenario

to emulate eight travel agents simultaneously performing these actions on

the flight reservation system. You will add two more users during the test

itself.

1 Add a script to the load test.

For the purpose of this tutorial, a script is provided that is similar to the one

you created. We recommend that you use the sample script.

Click the Browse button, and navigate to basic_scriptin the <LoadRunner

Installation>\Tutorial directory.

The script is displayed in the Available Scripts section and in the Scripts in

Scenario section.

Click OK. The LoadRunner Controller opens your scenario in the Design

tab.

2 Begin designing the load test scenario.

Check to see that the basic_scriptappears in the Group Name column of the

Scenario Groups window.

The Controller Window at a Glance

The Controller window’s Design tab contains three primary sections:

➤Scenario Schedule

➤Scenario Groups

➤Service Level Agreement

Scenario Schedule: In the Scenario Schedule section, you set the load

behavior to accurately portray user behavior. You determine the rate at

which load is applied to the application, the load test duration, and how the

load is stopped.

Design

Tab

Scenario Groups: You configure the Vuser groups in the Scenario Groups

section. You create different groups to represent typical users of your system.

You define the actions that they will run, the number of Vusers that will

run, and the machine that they will run on.

Service Level Agreement: When you design a load test scenario, you can

define goals or Service Level Agreements (SLAs) for the performance

metrics. When you run the scenario, LoadRunner gathers and stores

performance-related data. When you analyze the run, Analysis compares

this data against the SLAs and determines SLA statuses for the defined

measurements.

How do I generate a heavy load?

After you have added your scripts and defined the number of Vusers that

you want to run in the scenario, you can configure the load generator

machines.

Load generators are the machines that create load on the application by

runningVusers. You can use a number of load generator machines, each

hosting many virtual users. In this section, you will learn about adding load

generators to the scenario and testing the load generator connection.

1 Add a load generator.

Click the Load Generators button. The Load Generators dialog box opens,

showing details for the localhostload generator machine.

In this tutorial, you will use your local computer as the load generator

(included in the scenario by default). The status of the localhostload

generator is Down. This indicates that the Controller is not connected to the

load generator.

Note: In a typical production system, you would have a few load generator

machines, each hosting many Vusers. You would add additional machines

by clicking the Add button in the Load Generators dialog box, and entering

the machine name and platform type in the Add New Load Generator dialog

box.

2 Test the load generator connection.

When you run a scenario, the Controller connects to the load generators

automatically. However, you can test the connections before trying to run a

scenario.

Select the localhostload generator and click Connect.

The Controller attempts to connect to the load generator machine. When a

connection has been made, the status changes from Down to Ready.

Click Close.

How do I emulate real load behavior?

After you have added your load generator machines, you are ready to

configure load behavior.

Typical users do not log on and off the system at precisely the same time.

LoadRunner allows users to gradually log on to and off the system. It also

lets you determine the duration of the load test, and the way in which the

scenario is stopped.

You configure the load behavior for a manual scenario in the Scenario

Schedule area of the Controller window. The Scenario Schedule section is

divided into two sections, the Schedule Definition pane and the Schedule

Actions grid.

How do I emulate different types of users?

Now that you have configured a load schedule, you will specify how your

Vusers will behave during the test.

When emulating a real user, you need to consider the user’s actual behavior.

Behavior refers to the time that a user takes to pause between actions, the

number of times he repeats an action, and so on.

In this section, you will learn more about LoadRunner’s run-time settings,

and you will enable think time and logging.

1 Open the Run-Time settings.

In the Design tab, select the script and click the Run-Time Settings button.

The Run-Time settings are displayed.

The Run-Time settings let you emulate different kinds of user activity and

behavior. They include:

➤Run Logic: the number of times a user repeats a set of actions

➤Pacing: the time to wait before repeating the action

Note: After the initial debugging run, extended logging is not recommended

for a load test. It is only enabled for the purposes of this tutorial to provide

information for the Vuser Output log.

Click OK to close the Run-Time settings.

How do I monitor the system under load?

Now that you have defined how your Vusers will behave during the test, you

are ready to set up your monitors.

While creating heavy load on an application, you want to see how the

application performs in real time and where potential bottlenecks exist. You

useLoadRunner’s suite of integrated monitors to measure the performance

of every single tier, server, and component of the system during the load

test. LoadRunner includes monitors for a variety of major backend system

components including Web, application, database, and ERP/CRM servers.

For instance, you can select a Web Server Resources monitor according to

the type of Web server that is running. You can purchase a license for the

relevant monitor, for example IIS, and use this monitor to pinpoint

problems reflected in the IIS resources.

In this section, you will learn how to add and configure the Windows

Resources monitor. You can use this monitor to determine the impact of

load on your CPU, disk, and memory resources.

2 Select the monitored server.

In the Monitored Server Machines section of the Windows Resources dialog

box, click Add. The Add Machine dialog box opens.

 

Type localhostin the Name box.(If your load generator was running off a

different machine you would type the server name or IP address of that

machine.) In the Platform box, enter the platform on which the machine

runs. Click OK.

The default Windows Resources measurements are displayed in the

Resource Measurements on <server machine>pane.

3 Activate the monitor.

Click OK in the Windows Resources dialog box to activate the monitor.