title: nginx reverse proxy setup, 768 worker_connections are not enough while connecting to upstream
body: <p>I'm setting up a reverse proxy on nginx. 
  I've a virtual host setup with server_name <code>phpmyadmin.lvh.me</code> and I want to redirect <code>localhost/phpmyadmin</code> to <code>phpmyadmin.lvh.me</code> as a reverse proxy. </p>
  
  <p>This is my default configuration file:</p>
  
  <pre><code>upstream phpmyadmin {
      server phpmyadmin.lvh.me:80;
  }
  
  server {
      listen 80 default_server;
      listen [::]:80 default_server ipv6only=on;
  
      root /usr/share/nginx/html;
      index index.html index.htm;
  
      # Make site accessible from http://localhost/
      server_name localhost;
  
      location /phpmyadmin/ {
          proxy_pass http://phpmyadmin;
      }
  
      location / {
          # First attempt to serve request as file, then
          # as directory, then fall back to displaying a 404.
          try_files $uri $uri/ =404;
          # Uncomment to enable naxsi on this location
          # include /etc/nginx/naxsi.rules
      }
  
      # Only for nginx-naxsi used with nginx-naxsi-ui : process denied requests
      #location /RequestDenied {
      #   proxy_pass http://127.0.0.1:8080;    
      #}
  
      #error_page 404 /404.html;
  
      # redirect server error pages to the static page /50x.html
      #
      #error_page 500 502 503 504 /50x.html;
      #location = /50x.html {
      #   root /usr/share/nginx/html;
      #}
  
      # pass the PHP scripts to FastCGI server listening on 127.0.0.1:9000
      #
      location ~ \.php$ {
          fastcgi_split_path_info ^(.+\.php)(/.+)$;
          # NOTE: You should have "cgi.fix_pathinfo = 0;" in php.ini
  
          # With php5-cgi alone:
          #fastcgi_pass 127.0.0.1:9000;
          # With php5-fpm:
          fastcgi_pass unix:/var/run/php5-fpm.sock;
          fastcgi_index index.php;
          include fastcgi_params;
      }
  
      # deny access to .htaccess files, if Apache's document root
      # concurs with nginx's one
      #
      #location ~ /\.ht {
      #   deny all;
      #}
  }
  </code></pre>
  
  <p>but when I tried accessing <code>localhost/phpmyadmin</code> it is throwing internal server error with error message:</p>
  
  <pre><code>2015/02/08 22:13:21 [alert] 19470#0: *2293 768 worker_connections are not enough while connecting to upstream, client: 127.0.0.1, server: localhost, request: "GET /phpmyadmin/ HTTP/1.0", upstream: "http://127.0.0.1:80/phpmyadmin/", host: "phpmyadmin"
  </code></pre>
  
  <p>The configuration of <code>phpmyadmin.lvh.me</code> is written in different conf file in site-available directory. </p>