[rabbitmq-discuss] Scaling Throughput with Highly Available Queues

Tue Mar 19 20:49:03 GMT 2013

Richard,

On 19/03/13 20:40, Richard Raseley wrote:
> Is it correct to say that adding nodes to a cluster in which you are
> exclusively using highly available queues will not increase performance
> (and in fact me degrade it) but will instead simply increase resiliency?
> My thought is that the overhead for each message publish would increase
> linearly as you added nodes for a cluster, as each of those messages
> have to be replicated to each node (e.g. there is going to be more
> latency in acknowledging the publishing of a 1KB message to a 2 node
> cluster vs. a 10 node cluster.

That's about right. For the 'all' ha-mode. However, ...

> Furthermore, if there is a desire to add throughput capacity while still
> utilizing highly available queues, would it be best to add additional
> clusters with mirrored configurations (e.g. 2x 2-node clusters) and put
> them behind the same load balancer?

You could switch to the 'exactly' ha-mode - see 
http://www.rabbitmq.com/ha.html#genesis - where queues are mirrored on a 
given number of nodes, regardless of how many nodes there are in the 
cluster in total.

Regards,

Matthias.