[rabbitmq-discuss] RabbitMQ QUEUE MESSAGES

Tue Jul 2 17:43:16 BST 2013

Hi,

On 02/07/13 17:17, rabbit15 wrote:
> My server hardware is 32 CPUs and 64 GB RAM, I don't think I
> need better hardware, 

I agree.

> it turn on horrible flow control which prevents sending as fast as I
> need. Please tell me how can I turn off flow control.

Your publishers probably require more bandwidth than your disk / IO
subsystem provides. As soon as messages start paging to disk the overall
queue throughput drops to below the level that publishers can tolerate.

The broker pre-emptively starts paging messages before all RAM is
occupied to prevent a dramatic performance drop when memory does run
out. You can delay the onset of paging by increasing the
vm_memory_high_watermark setting. You mentioned previously that you set
this to 100% (1.0), but you can set it beyond 100% to utilise even more
RAM before paging starts. The risk with this approach is that the server
could crash by running out of RAM.

-Emile