Choosing a message broker for Internet of things based on load testing

This article describes load testing common IoT message brokers under various configurations. The list of message brokers is represented by Mosquitto, EMQX, Active MQ, and Aedes. The NBomber library was chosen as the main tool for load testing. Based on this library, scenarios for stress testing brokers were developed. Each scenario was applied to the corresponding number of connections, message size, and QoS level. A custom client (called "message listener") was developed to handle errors. The collected data included the number of requests processed per second, the latency of sending messages, the number of errors, and the CPU utilization. Based on the obtained data, a normalized broker rating was proposed and applied. The best message broker can be selected by calculating the normalized broker score for each load scenario and merging all the calculated results into a pivot table. The best message broker is selected from the result table.