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Sunday, March 1, 2009

Using Windows desktop connection in LoadRunner

Remote Desktop Connection (part of the Terminal Services that comes with Winodows XP) is not as reliable with LoadRunner as Remote Administrator.

To keep Windows Remote Desktop Connection sessions from timing out during a test, the Terminal Services on each machine should be configured as follows:

1. Click Start, point to Programs (or Control Panel), Administrative Tools and choose Terminal Services Configuration.
2. Open the Connections folder in tree by clicking it once.
3. Right-click RDP-Tcp and select Properties.
4. Click the Sessions tab.
5. Make sure "Override user settings" is checked.
6. Set Idle session limit to the maximum of 2 days instead of the default 2 hours.
7. Click Apply.
8. Click OK to confirm message "Configuration changes have been made to the system registry; however, the user session now active on the RDP-Tcp connection will not be changed."

Make sure that when you do this you're not violating one of your corporation's security policies.
Terminal Server only allows two simultaneous connections. To disconnect from a session, do not click "X" on the remote desktop window but click Start and Log Off

How LoadRunner works?

Unlike a WinRunner workstation which emulates a single user's use of a client, LoadRunner can emulate thousands of Virtual Users.

Load generators are controlled by VuGen scripts which issue non-GUI API calls using the same protocols as the client under test. But WinRunner GUI Vusers emulate keystrokes, mouse clicks, and other User Interface actions on the client being tested Only one GUI user can run from a machine unless LoadRunner Terminal Services Manager manages remote machines with Terminal Server Agent enabled and logged into a Terminal Services Client session.

During run-time, threaded vusers share a common memory pool. So threading supports more Vusers per load generator.

The Status of Vusers on all load generators start from "Running", then go to "Ready" after going through the init section of the script. Vusers are "Finished" in passed or failed end status. Vusers are automatically "Stopped" when the Load Generator is overloaded.

No additional license is needed to monitor standard web (HTTP) servers (Apache, IIS, and Netscape).

To use Web Services Monitors for SOAP and XML, a separate license is needed, and vUsers require the Web Services add-in installed with Feature Pack (FP1)

Saturday, February 28, 2009

LoadRunner Architecture

LoadRunner works by creating virtual users who take the place of real users operating client software, such as Internet Explorer sending requests using the HTTP protocol to IIS or Apache web servers.
Requests from many virtual user clients are generated by "Load Generators" in order to create a load on various servers under test.
These load generator agents are started and stopped by Mercury's "Controller" program. The Controller controls load test runs based on "Scenarios" invoking compiled "Scripts" and associated "Run-time Settings".

Scripts are crafted using Mercury's "Virtual user script Generator" (named "V U Gen"), It generates C-language script code to be executed by virtual users by capturing network traffic between Internet application clients and servers.

With Java clients, VuGen captures calls by hooking within the client JVM. During runs, the status of each machine is monitored by the Controller.

At the end of each run, the Controller combines its monitoring logs with logs obtained from load generators, and makes them available to the "Analysis" program, which can then create run result reports and graphs for Microsoft Word, Crystal Reports, or an HTML webpage browser.

Each HTML report page generated by Analysis includes a link to results in a text file which Microsoft Excel can open to perform additional analysis.

Errors during each run are stored in a database which can be read using Microsoft Access

Where is Load Testing usually done?

The Load testing is carried in the controlled environment based on the requirement specs from the client the Load Test Plan followed with the scenarios are created & executed to match the requirements. To speak more precisely the Load testing Episode is carried once the Performance exercise is done, finding the System bottlenecks & Tuning and Fixed.

How do we do performance and Load Testing using LoadRunner?

LOAD TESTING: First generate the script using virtual user generator or astra quick test. Run the generated script in the load runner controller. While doing this run time settings are to be modified according to the specifications required. Eg. ignore think time, ignore content in the application etc..
In run time settings, choose the numbers of virtual users to run the application simultaneously. let all the virtual users begin from the same point. Once you click start scenario the load test begins.
Points to consider after stopping the application:
1, The number of throughputs and hits per sec have to increase as the number of virtual users increases. If throughputs flattens, we can say there are network problems and if hits per second flattens, we say connection/network problems.
2, check that all the virtual users passed the application within the specified Response Time.

How many types of graphs have LoadRunner?

There are 5 graphs on Load Runner.
1) Hits per second graph
2) pages download per second graph
3) Transaction response time (under load) graph
4) Transaction response time (percentile) graph and
5) Network delay time graph

How can we set the number of vuser in LoadRunner?

When Creating Scenario in Controller we have to add the particular script which we want to run. There we have to set the number of Vusers to run for that script. but you have to add Vusers depending on the your LoadRunner license for how many Vusers it sponsors.