[rabbitmq-discuss] RabbitMQ hangs, does not accept connections
simon at rabbitmq.com
Fri Mar 9 12:37:10 GMT 2012
On 09/03/12 07:57, Dmitri Minaev wrote:
> Oh... Thanks. I thought, that if TCP connection is accepted, number of
> file descriptors should have no effect on the further events, since
> the socket already exists. Even now I can connect to port 5672 on that
> server, but AMQP does not respond.
I think at this point it hasn't actually allocated the FD, so it can't
> If I understand correctly, the number of file descriptors used by
> RabbitMQ in normal situation is roughly equal to the number of
> `rabbitmqctl list_connections` + some constant (~30)? In case of that
> hanging server, the number of AMQP connections never was close to the
> FD limit (ulimit -n is 1024, fs.file-max = 1605698). The graph
> reflecting the number of open AMQP connections is attached to this
It's not really a constant, but to a first approximation, yes.
Ultimately, the error I saw being passed up from the OS was ENFILE -
that's pretty unambiguous :)
It's possible that if you're churning connections then "closed"
connections in FIN_WAIT2 could account for the majority of the used FDs.
In 2.8.0 we'll set SO_LINGER to 0 to prevent this.
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