[rabbitmq-discuss] How to plan for RAM?

Mon Apr 9 14:17:59 BST 2012

Hi all!

I'm trying to determine how much RAM I need for my 2 node cluster. I
use VMs at Rackspace.

I currently have 2x 4 GiB RAM nodes, but I consistently hit my VM high
memory watermark. I have one topic exchange, with about 8 queues. The
routing keys are all left-anchored: my queues all use routing keys of
the form "a.#" or even "#". During normal operation, I generate
between 5 and 20 messages per second, and at peak, more than 2000. I
have 2 queues which use a routing key of the form "#", and I spread
the load so I have one queue on each node. The other queues have much
more restrictive routing keys, but I tried to spread the load as well.
The messages are compressed XML representations of Java and Scala
objects. Most messages are under 2 KiB, with some reaching as high as
2 MiB. Consumers can keep up with producers, and the queues are empty
90%+ of the time.

Any tips on how I can plan for my RAM?

Thanks!
François