[rabbitmq-discuss] RabbitMQ instances

Thu Apr 26 14:45:46 BST 2012

Hi Nabeel,

On 26/04/12 14:21, Nabeel Akhtar (Abu Yousuf) wrote:
> If there is only one broker and number of clients increase, how well
> will it scale? Do you think after a certain level RabbitMQ broker will
> become a bottleneck?

Yes it may become a bottleneck, because an overloaded broker may use TCP
backpressure to prevent message producers from publishing.

Message producers may decide simply to drop messages if the broker
applies backpressure. If the message flood is temporary and some message
loss can be tolerated then this may be an acceptable option.

You should also consider using a cluster and multiple queues in order to
parallelise the workload better.

If message consumers are not able to keep up with publishers then the
broker is more likely to come under pressure and become a bottleneck.
The best way to avoid this is to ensure that consumers are able to
process messages fast enough.

> Is it possible to have backup RabbitMQ brokers so if the original one
> goes down, back-up becomes active?

For high availability you should look at mirrored queues:
http://www.rabbitmq.com/ha.html

-Emile