Which MQTT server for > 1M connections -

How would you do this with a budget of some million to build an MCT server form?

It should have the following properties:

• Support for 4-5m connections in all data centers.
• 300k messages of approximately 1kb each / s
• Geographic redundancy
• Message can not be lost QOS1
• On the same subject Will publish, but subscribe to your own unique topic. It means 4-5 million topics.

MQTT server brokers can be found here:

Although capabilities are not usually published.