The question came up in the course of using RabbitMQ of how to ensure that if something catastrophic happens that the system wouldn’t lose any data due to either side of the queue coming down unexpectedly.

We had the exchange and the queues both set as ‘durable’, which we thought should cover everything. Right?

Apparently not.

In addition to the exchange and queues needing to be durable, the messages themselves must be flagged as ‘persistent’.