[rabbitmq-discuss] Cluster Memory Usage

Mon Nov 21 22:50:39 GMT 2011

Travis,

On 21/11/11 22:16, Travis wrote:
> Yes.  We've seen this problem when there are only a few dozen messages
> and when there are hundreds of thousands.
>
> Basically, it seems like the slave is always taking up 2-5x the amount
> of memory that the master uses.

In my tests the slave uses a bit less memory than the master, which is 
what I would expect in a relatively lightly loaded system when there are 
no connections to the slave node.

> Looking at the two servers, the slave shows that it's beam.smp has
> spent 12 more hours on cpu than the beam.smp on the master.  This
> doesn't make sense to me if the slave is doing less work because it's
> only handling traffic coming from the master.

That's odd indeed. In my test I see the slave getting by with less than 
half the CPU utilisation of the master.

Do you see this memory and CPU pattern - with the slave using more than 
the master - all the time, including shortly after a restart?

I still haven't got a good trail to follow here. One thing to look at is 
the output of 'rabbitmqctl report' when the system is in the "excessive 
memory use" state. Please send us that.

Regards,

Matthias.