FMQ Cluster Benchmark

FMQ Benchmark

The following benchmark focuses on a single-node MQTT scenario and is used as a capacity reference before scaling to a cluster.

Test Background

As MQTT-based business systems grow, message communication performance becomes a key requirement. This benchmark evaluates a 4-core 8 GB single-node server running FMQ MQTT Broker and provides data for future capacity planning.

Test Environment

Item	Description
MQTT server	One lightweight 4-core 8 GB server running FMQ MQTT Broker
Benchmark clients	Four lightweight 4-core 8 GB servers simulating large numbers of MQTT clients
Operating system	Use a tuned Linux system with optimized file descriptors and network buffers
Benchmark tool	`emqtt_bench`, used to control connection count, message rate, and message size

Test Indicators

Connection count: the number of clients a single MQTT node can carry.
Concurrent connections: the upper bound of simultaneous client connections.
Message send rate: messages sent by clients per unit time.
Message receive rate: messages received and processed by the server per unit time.
Message latency: time from client send to server acknowledgement.
CPU usage and memory usage during benchmark runs.

Test Scenarios

Increasing Concurrent Connections

Start from 100 concurrent connections and increase by 500 each round until 5000. Keep each level stable for 10 minutes and collect metrics. Distribute connections across the four benchmark clients to keep load balanced.

Fixed Connections With Increasing Message Rate

Set connection counts to 1000, 2000, 3000, 4000, and 5000. Under each connection level, start at 100 messages per second and increase gradually until clear bottlenecks appear, such as sharp latency growth or message loss.