[rabbitmq-discuss] Generally known configuration for open file descriptor limits

Tue Sep 21 15:57:36 BST 2010

On Tue, Sep 21, 2010 at 03:50:37PM +0100, Marek Majkowski wrote:
> You definitely need more file descriptors than number of connections.
> 
> As a rule of thumb I'd suggest:
>  - 1 file descriptor for every connection
>  - 3+ file descriptors for every queue that might be written to disk

Err, that's actually a max of 1 per queue.

And that is a rule of thumb - there is no problem with running a million
queues off 1000 fds - rabbit will just cope as necessary, but you might
find performance is improved with additional fds.

If your ulimit is X, then the number of connections you'll be allowed to
open is (0.9*(X - 100))-2. Thus that should give you a minimum (via
rearrangement). More fds never hurt!

Matthew