Wednesday, April 6, 2011

Introducing Vusers

Vusers emulate the actions of human users by performing typical business
processes in your application. The actions that a Vuser performs during the
recording session are described in a Vuser script.

HP’s tool for creating Vuser scripts is the Virtual User Generator, VuGen. You
use VuGen to develop a Vuser script by recording a user performing typical
business processes on a client application. VuGen records the actions that
you perform during the recording session, recording only the activity
between the client and the server. Instead of having to manually program
the application’s API function calls to the server, VuGen automatically
generates functions that accurately model and emulate real world situations.

During recording VuGen monitors the client end of the database and traces
all the requests sent by the user and received from the user, to the server.










During playback, Vuser scripts communicate directly with the server by
executing calls to the server API. When a Vuser communicates directly with
a server, system resources are not required for the client interface. This lets
you run a large number of Vusers simultaneously on a single workstation,
and enables you to use only a few testing machines to emulate large server
loads.







In addition, since Vuser scripts do not rely on client software, you can use
Vusers to check server performance even before the user interface of the
client software has been fully developed.

Using VuGen, you can run scripts as standalone tests. Running scripts from
VuGen is useful for debugging as it enables you to see how a Vuser will
behave and which enhancements need to be made.

VuGen enables you to record a variety of Vuser types, each suited to a
particular load testing environment or topology. When you open a new test,
VuGen displays a complete list of the supported protocols.

















While running the Vusers, you gather information about the system’s
response. Afterwards, you can view this information with the Analysis tool.
For example, you can observe how a server behaved when one hundred
Vusers simultaneously withdrew cash from a bank’s ATM.



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