Service level agreements overview

Service level agreements (SLAs) are specific goals that you define for your load test scenario. After a scenario run, Analysis compares these goals against performance related data that was gathered and stored during the course of the run, and determines whether the SLA passed or failed.

You can define and edit SLAs in Controller or in Analysis.

Depending on the measurements that you are evaluating for your goal, SLA status is determined in one of the following ways:

SLA Type Description
SLA status determined at time intervals over a timeline

Analysis displays SLA statuses at set time intervals over a timeline within the run. At each time interval in the timeline—for example, every 10 seconds—Analysis checks to see if the measurement's performance deviated from the threshold defined in the SLA.

Measurements that can be evaluated in this way:

  • Transaction Response Time (Average)

  • Errors per Second

SLA status determined over the whole run

Analysis displays a single SLA status for the whole scenario run.

Measurements that can be evaluated in this way:

  • Transaction Response Time (Percentile)

  • Total Hits per run

  • Average Hits (hits/second) per run

  • Total Throughput (bytes) per run

  • Average Throughput (bytes/second) per run

  • Passed Transactions Ratio: SLA status is determined by calculating the percentage of passed transactions out of total transactions, and comparing the result to the percentage threshold defined in the SLA settings.
APDEX status determined over the whole run

Analysis displays an APDEX score for the whole scenario run. APDEX is an open standard to measure satisfaction with the response time. It is based on a ratio value of the number of satisfied and tolerated requests, against the total requests made, for each transaction. The end score is a value between 0 and 1. The higher the value, the better the performance of the measured metric.

Measurements that can be evaluated in this way:

  • Transaction Response Time (APDEX)

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