<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body dir="auto"><div>The kicker is if there's a load balancer between then the load balancer would act as a proxy to the various nodes - so it has a limited number of connections it can make to a single server.</div><div><br></div><div>So a suggestion - remove the load balancer and even cluster - start with a single box. See how many connections it can handle solo. Though if possible limited connections with multiple channels is a better idea.</div><div><br></div><div>Jason</div><div><br>Sent from my iPhone</div><div><br>On Jan 28, 2013, at 11:43 AM, Tony Garnock-Jones <<a href="mailto:tonygarnockjones+rabbitmq@gmail.com">tonygarnockjones+rabbitmq@gmail.com</a>> wrote:<br><br></div><blockquote type="cite"><div><div dir="ltr">Hi Jason,<div class="gmail_extra"><br><div class="gmail_quote">On 26 January 2013 12:14, McIntosh Jason <span dir="ltr"><<a href="mailto:mcintoshj@gmail.com" target="_blank">mcintoshj@gmail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">with TCP/IP communications an interface only has 65k ports (roughly).</blockquote>
<div><br></div><div style="">If my understanding is correct, this is less of a limitation than it seems.</div><div style=""><br></div><div style="">TCP connections are identified by a quad of source-IP, source-port, dest-IP and dest-port. So if you have a service listening on 10.1.2.3 port 5672, the connections will, on the server, look like</div>
<div style=""><br></div><div style=""><div> <a href="http://192.168.34.56:43556">192.168.34.56:43556</a> <--> <a href="http://10.1.2.3:5672">10.1.2.3:5672</a></div><div><div> <a href="http://172.16.99.104:50602">172.16.99.104:50602</a> <--> <a href="http://10.1.2.3:5672">10.1.2.3:5672</a></div>
</div><div><div> <a href="http://10.202.14.66:61082">10.202.14.66:61082</a> <--> <a href="http://10.1.2.3:5672">10.1.2.3:5672</a></div></div><div><br></div><div style="">and so on. In each case, the IP/port of the server's end of the socket is the same. This means that you're not limited to 65k TCP connections per interface; instead, you're limited to approximately 2^48 = 281,474,976,710,656 connections *per listening socket* :-)</div>
<div style=""><br></div><div style="">The rest of your message is spot on, in particular regarding file descriptor and memory limits in the operating system and C libraries.</div><div style=""><br></div><div style="">Regards,</div><div style="">
Tony</div><div style=""><br></div></div></div><div><br></div>-- <br>Tony Garnock-Jones<br><a href="mailto:tonygarnockjones@gmail.com" target="_blank">tonygarnockjones@gmail.com</a><br><a href="http://homepages.kcbbs.gen.nz/tonyg/" target="_blank">http://homepages.kcbbs.gen.nz/tonyg/</a>
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