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i set up nginx as the reverse proxy server in front of an apache + mod_wsgi + python2.7 backend. nginx and apache are in 2 physical machines with 24 threads cpu (Xeon E5645). if i run the "ab -c 20000 -n 40000" bench test directly to the apache server, it worked fine, in fact the apache server could handle an "ab -c 20000 -n 80000" bench test. but when i put the nginx in front of apache (in another server as powerful as the one apache resides), the bench test will fail on around 32000 requests.

here is the nginx config file:

worker_processes  24;
events {
    worker_connections  65536;

    server {
        listen       80;
        server_name  example.net;

        location / {
            proxy_pass  http://example.org;

net.core.somaxconn has been adjusted to 1048576

so what could be the problem?

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what is the spec of the Nginx server? –  TiernanO Sep 30 '11 at 11:43
Xeon E5645, 128G ram, same as the apache server –  xpu Oct 3 '11 at 7:11
I remember reading somewhere, but cant find the link currently, some simular issue... it eneded up being a problem with the machine running AB, and it ran out of memory... Servers were grand. are you running AB on a simular spec-ed machine? can you run it on multiple machines? –  TiernanO Oct 4 '11 at 16:25
yes, i do run ab on a powerful machine, let's say, there are 3 servers with the same 64G ram, Xeon E5645, i have one of them as the nginx server, one as the apache backend server, and another as the client to host ab, it's not like that the ab was able to exhaust the server. –  xpu Oct 5 '11 at 8:27
it might not be able to exaust the server, but it might exaust the connections... See if you can run a couple machines using AB and seeif that works... As i said, the article i read (think it could be here on serverfault, but cant find the link off hand), it was AB that was causing the problem, not the servers... –  TiernanO Oct 5 '11 at 11:33

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