Define service level agreements - use-case scenario

This use-case scenario describes how to define a service level agreement (SLA) for Average Transaction Response Time.

In this use case, the administrator of the Web Tours website would like to know when the average transaction response time for booking a flight and searching for a flight exceeds a certain value. The scenario includes a script that includes the following transactions: book_flight and search_flight.

Start the SLA wizard

In Analysis, select Tools menu > Configure SLA Rules > Service Level Agreement window > New button.
Select the measurements

On the Select a Measurement for Your Goal page, choose Transaction Response Time box and select Average.
Select the transactions to evaluate in your goal

On the Select Transactions page, in the Available Transaction pane, move the book_flight and search_flight transactions to the Selected Transactions pane.
Set a load criteria

On the Select Load Criteria page, select the load criterion to consider when evaluating the average transaction response time.

In this use case, to see the effect that various quantities of Vusers running on the system has on the average transaction response time of each transaction, in the Load Criteria box, select Running Vusers.

Then set the value ranges for the running Vusers. Valid load value ranges are consecutive—there are no gaps in the range—and span all values from zero to infinity.

Consider less than 20 Vusers to be a light load, 20 – 50 Vusers an average load, and 50 Vusers or more a heavy load. Enter these values in the Load Values boxes.
Set thresholds

On the Set Threshold Values page, you define the acceptable average transaction response times for the transactions, taking into account the defined load criteria.

In this case, define the same threshold values for both transactions as follows: for a light load, a reasonable average response time can be up to 5 seconds, for an average load, up to 10 seconds, and for a heavy load, up to 15 seconds.

Tip: To define the same thresholds for all the transactions, you can type the values in the table nearer the bottom of the Set Threshold Values page, and click Apply to all transactions.
Define a tracking period - optional

When SLA statuses for a measurement are determined at time intervals over a timeline, the frequency of the time intervals is determined by the tracking period.

This step is optional because an internally-calculated tracking period of at least 5 seconds is defined by default. You can change the tracking period in the Advanced Options dialog box:
1. In the Service Level Agreement pane (Controller) or window (Analysis), click the Advanced button.
2. Select Tracking period of at least X seconds, and select a tracking period.
View results

When analyzing your scenario run, Analysis applies the SLA settings to the Summary Report. For example, it displays the worst performing transactions in terms of defined SLAs, how specific transactions performed over set time intervals, and overall SLA statuses.