[rabbitmq-discuss] HA policies

Sat Sep 3 06:30:42 BST 2011

Brad,

On 03/09/11 06:05, Brad Knowles wrote:
> On Sep 2, 2011, at 11:25 PM, Matthias Radestock wrote:
>>> The "all nodes" setting really isn't a solution to that.
>>
>> Why is that?
>>
>> I would have thought that 'all' is a sensible option for the
>> majority of users that want HA. And it does not require argument
>> changes when the topology evolves.
>
> Mirroring the queue across all nodes means that you don't have any
> scalability [...], because all nodes will see all traffic

Indeed, and that is one reason why more controls are desirable in some 
use cases, as I acknowledged in my previous email.

However, I suspect most users will come to HA from single instance 
setups and move to small 2-3 node clusters for the sole purpose of 
attaining HA, and not, simultaneously, for reasons of scalability.

For them the 'all' policy is (close to) ideal. And it *does* insulate 
the app from topology changes.

Matthias.