[rabbitmq-discuss] RabbitMq not honouring high_watermark setting?

Wed Jul 13 13:04:27 BST 2011

On 13/07/11 12:55, Dan B wrote:
> I should have RTFM a bit more thoroughly.
> 
>>> Thus when RabbitMQ can't recognize your platform, if you actually have 8GB RAM
>>> installed and you want RabbitMQ to throttle producers when the server is using
>>> above 3GB, set vm_memory_high_watermark to 3
> 
> On my server, vm_memory_high_watermark = n results in a watermark of
> 2n for some reason. I've set it to 1.5 (3gb), I'm not sure if Rabbit
> can access all of that though, probably not.

You are certain to run out of memory at some point if you do that.
Unfortunately the Windows Erlang VM is 32bit and limited to 2Gb. Some
versions of Windows support an alternative memory model that may allow a
suitably patched Erlang VM access to slightly more memory, but I don't
know of anyone succeeding in making it work:

http://support.microsoft.com/default.aspx?scid=kb%3BEN-US%3B297812

-Emile