The HiveMQ MQTT broker is a distributed, stateful application, which naturally requires a fair amount of read/write operations to the hard disc. This means that choosing the right type of storage, when using a cloud provider can have a positive impact on HiveMQ’s overall performance.
For AWS we recommend the following:
io1 instances offer constant I/O whereas gp2 capabilities increase at larger sizes.
900 IOPS will usually suffice. gp2 instances will reach this at a much lower price point than io1 instances. We consider 300GB instance size for gp2 a sweet spot for most use cases.