VU Tab

The VU tab can be accessed by clicking directly on it or clicking on the number of VU’s field of the relevant Task Group scenario. It is here where the number of virtual users and the ramp up rates for that particular Task Group scenario are specified.

In this example 500 VU’s have been assigned to this task group and a ramp up rate has been specified of 5 minutes (300s), additionally a stepped ramp up has been specified with 100 VU’s per block and an plateau interval of 15 minutes (900s), this approach is useful in a stress test where the upper limits of the application are not know. In fact the results can be set to automatically break down into sets of results per plateau enabling multiple results from one test execution.

Other parameters are optional but can be useful to set, all of them are described below, one to pay particular attention to is ‘Save Request Details’:

Nb VU’s: The number of virtual users to assign to the Task Group scenario in focus.

Ramp up Time (s): The amount of time AgileLoad should take to introduce the users into the test, this is necessary as simple adding all the users in one go will very often cause the application to fail or cause a rippling effect in the load.

Ramp up options: This is an optional set of parameters to enable a stepped approach to the ramp up.

Nb VU’s / batch: The number of VU’s that should be introduced per load increase step.
Interval: The period of time that the test should execute between each step with an increase in the Load

Data Collection (%): Normally this value is left as default, however it may be a good idea to reduce this percentage in a very large test or very long test such as a soak test. This value relates to the sampling rate AgileLoad uses when collecting statistics relating to the timers and page timers in the script.

HTTP Results (%): Also this should be left as default or reduced for very large or long duration tests where potentially huge amounts of data can be amounted. AgileLoad collects timing information for every single object on the pages it retrieves from the target application including main requests and requests for images, java scripts, style sheets and so on. By default a 10% sample of this data is collected.

Save Request Details: is used to specify the action of AgileLoad upon the failure of a request, turning this on can be very useful for diagnosing the reasons that a test has failed. By default it is turned off, it is recommended to turn this on and set it to ‘On Check Failed’, this will enable the hyperlinks to request details in the failed checks view in the results section. AgileLoad will only, ever save the first <Max Number of Requests per User> request details.

User (%): In the case that ‘always’ is selected in the Save Request Details drop down then this will control the percentage of users whose request details are saved.

Ignore: AgileLoad will not save request details relating to requests of the type specified in this list, this is best left as default as the types specified here relate to static requests which will rarely cause any problems during a load test.

Max number of requests per user: The number of requests that will be saved per user. See Save Request Details.


 

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