Single Active Consumer queues

[DavidBoike]

Single Active Consumer queues enable an automatic failover where only one consumer is allowed to process messages from a queue at a given time, but when it fails or disconnects it seamlessly goes over to another consumer that was, up to that point, sitting in wait.

From the documentation, it sounds like this is normally used to do in-order processing, but that's not the only use case.

From a user:

I can think of several scenarios where single active consumer is a good feature. In our case it's an external system outside of our control that does not handle concurrency very well, and we do always use two instances of our modules for HA purposes. This would be a very easy solution, as this would create an Active / Passive scenario for this specific module, where no custom implementation would be necessary. Performance is not a concern in our scenario.

It's possible to create the queues manually, but currently impossible to have NServiceBus use this option when creating queues on the user's behalf.