<div dir="ltr">Matthias,<div><br></div><div>Thank you for your quick response. With regard to your suggestion on using a specific replica count via the "exactly" ha-mode - wouldn't there still be a bottleneck in the master node of the cluster? My understanding is that it has a hand in all operations (obviously true in a cluster with ha queues), but that it is in-line with all non-publishing operation. Is this a correct understanding?</div>
<div><br></div><div>Regards,</div><div><br></div><div>Richard</div></div><div class="gmail_extra"><br><br><div class="gmail_quote">On Tue, Mar 19, 2013 at 1:49 PM, Matthias Radestock <span dir="ltr"><<a href="mailto:matthias@rabbitmq.com" target="_blank">matthias@rabbitmq.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Richard,<div class="im"><br>
<br>
On 19/03/13 20:40, Richard Raseley wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Is it correct to say that adding nodes to a cluster in which you are<br>
exclusively using highly available queues will not increase performance<br>
(and in fact me degrade it) but will instead simply increase resiliency?<br>
My thought is that the overhead for each message publish would increase<br>
linearly as you added nodes for a cluster, as each of those messages<br>
have to be replicated to each node (e.g. there is going to be more<br>
latency in acknowledging the publishing of a 1KB message to a 2 node<br>
cluster vs. a 10 node cluster.<br>
</blockquote>
<br></div>
That's about right. For the 'all' ha-mode. However, ...<div class="im"><br>
<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Furthermore, if there is a desire to add throughput capacity while still<br>
utilizing highly available queues, would it be best to add additional<br>
clusters with mirrored configurations (e.g. 2x 2-node clusters) and put<br>
them behind the same load balancer?<br>
</blockquote>
<br></div>
You could switch to the 'exactly' ha-mode - see <a href="http://www.rabbitmq.com/ha.html#genesis" target="_blank">http://www.rabbitmq.com/ha.<u></u>html#genesis</a> - where queues are mirrored on a given number of nodes, regardless of how many nodes there are in the cluster in total.<br>
<br>
Regards,<br>
<br>
Matthias.<br>
</blockquote></div><br></div>