[rabbitmq-discuss] RabbitMQ memory limit and shutting down

Tue Aug 13 14:46:14 BST 2013

On 12/08/2013 12:54PM, Nikita Trophimov wrote:
> First case we can control by ourselves (for example, via external
> utility that monitors free resources on the server and stops creating
> new users).
> But what we can do with the second case (resources for messages
> initially was enough, but number of messages has increased)?

The cost per message in the message store index is constant (I think 
about 160 bytes IIRC) so you can make a reasonable guess how much memory 
this will use ahead of time.

The memory details in "rabbitmqctl status" or the management plugin can 
tell you how much of your memory has gone on the message store index.

To keep a limit on the number of messages, you could use fixed length 
queues or TTLs.

http://www.rabbitmq.com/ttl.html
http://www.rabbitmq.com/maxlength.html

> Or is the only way to avoid the situation with Y > X is conducting
> stress testing to understand the hardware requirements?

Well stress testing is always nice. But you should be able to do some 
back of the envelope calculations here.

Cheers, Simon

-- 
Simon MacMullen
RabbitMQ, Pivotal