The multiple design defects of RabbitMQ Mirrored Queues have been well documented by the community and acknowledged by the RabbitMQ team. In an age where new messaging systems are appearing that compete in the reliable messaging space, it is critical for RabbitMQ to improve its replicated queue story in order to continue to compete in that space. Which is why it is so exciting to see that the RabbitMQ team have been working hard to deliver a new replicated queue type based on the Raft consensus algorithm. Quorum queues are still in beta and as such are subject to change before release. Likewise, their capabilities will no doubt evolve and improve over future releases. There are currently limitations to the features of Quorum Queues but if data safety is your most important requirement then they aim to satisfy your needs.

In this post we'll going to look at the design of Quorum Queues and then in a later post we'll run a series of chaos tests to test the durability claims of this new queue type.

I recently spoke at the RabbitMQ Summit in London about using the Consistent Hash Exchange to maintain processing order guarantees while scaling out consumers. Afterwards I was asked why I don’t opt for the Sharding Plugin instead. One of the downsides of the Consistent Hash Exchange I spoke of in the talk was that you don’t get automatic queue assignment for your consumers. The Sharding Plugin makes an attempt to address this problem but doesn’t go all the way. In this post I’ll describe my issues with the Sharding Plugin.