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<p class="MsoNormal">Check if any of the sites you run on the server gets crawled by any crawlers around the time you see an increase – I know that a crawler such as Screaming Frog doesn’t handle servers that are capable of http2 connections and have it activated
for sites that are getting crawled, and will result in connections with a “waiting” state in nginx.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">It might be there’s other tools that behave the same way, but I’d personally look into what kind of traffic/requests happened that increased the waiting state a lot.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Best Regards,<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal" style="margin-left:36.0pt"><b><span style="font-size:12.0pt;color:black">From:
</span></b><span style="font-size:12.0pt;color:black">nginx <nginx-bounces@nginx.org> on behalf of Anoop Alias <anoopalias01@gmail.com><br>
<b>Reply-To: </b>"nginx@nginx.org" <nginx@nginx.org><br>
<b>Date: </b>Thursday, 7 September 2017 at 11.52<br>
<b>To: </b>Nginx <nginx@nginx.org><br>
<b>Subject: </b>Too many connections in waiting state<o:p></o:p></span></p>
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<p class="MsoNormal" style="margin-left:36.0pt"><o:p> </o:p></p>
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<p class="MsoNormal" style="margin-left:36.0pt">Hi, <o:p></o:p></p>
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<p class="MsoNormal" style="margin-left:36.0pt"><o:p> </o:p></p>
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<p class="MsoNormal" style="margin-left:36.0pt">I see sometimes too many waiting connections on nginx .<o:p></o:p></p>
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<p class="MsoNormal" style="margin-left:36.0pt"><o:p> </o:p></p>
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<p class="MsoNormal" style="margin-left:36.0pt">This often gets cleared on a restart , but otherwise pileup<o:p></o:p></p>
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<p class="MsoNormal" style="margin-left:36.0pt"><o:p> </o:p></p>
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<p class="MsoNormal" style="margin-left:36.0pt">###################<o:p></o:p></p>
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<p class="MsoNormal" style="margin-left:36.0pt">Active connections: 4930 <o:p></o:p></p>
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<p class="MsoNormal" style="margin-left:36.0pt">server accepts handled requests <o:p></o:p></p>
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<p class="MsoNormal" style="margin-left:36.0pt"> 442071 442071 584163 <o:p></o:p></p>
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<p class="MsoNormal" style="margin-left:36.0pt">Reading: 2 Writing: 539 Waiting: 4420 <o:p></o:p></p>
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<p class="MsoNormal" style="margin-left:36.0pt">#######################<o:p></o:p></p>
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<p class="MsoNormal" style="margin-left:36.0pt">[root@web1 ~]# grep keep /etc/nginx/conf.d/http_settings_custom.conf<o:p></o:p></p>
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<p class="MsoNormal" style="margin-left:36.0pt">keepalive_timeout 10s;<o:p></o:p></p>
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<p class="MsoNormal" style="margin-left:36.0pt">keepalive_requests 200;<o:p></o:p></p>
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<p class="MsoNormal" style="margin-left:36.0pt">keepalive_disable msie6 safari;<o:p></o:p></p>
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<p class="MsoNormal" style="margin-left:36.0pt">########################<o:p></o:p></p>
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<p class="MsoNormal" style="margin-left:36.0pt"><o:p> </o:p></p>
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<p class="MsoNormal" style="margin-left:36.0pt">[root@web1 ~]# nginx -V<o:p></o:p></p>
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<p class="MsoNormal" style="margin-left:36.0pt">nginx version: nginx/1.13.3<o:p></o:p></p>
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<p class="MsoNormal" style="margin-left:36.0pt">built by gcc 4.8.5 20150623 (Red Hat 4.8.5-11) (GCC) <o:p></o:p></p>
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<p class="MsoNormal" style="margin-left:36.0pt">built with LibreSSL 2.5.5<o:p></o:p></p>
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<p class="MsoNormal" style="margin-left:36.0pt">TLS SNI support enabled<o:p></o:p></p>
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<p class="MsoNormal" style="margin-left:36.0pt">configure arguments: --prefix=/etc/nginx --sbin-path=/usr/sbin/nginx --modules-path=/etc/nginx/modules --with-pcre=./pcre-8.41 --with-pcre-jit --with-zlib=./zlib-1.2.11 --with-openssl=./libressl-2.5.5 --conf-path=/etc/nginx/nginx.conf
--error-log-path=/var/log/nginx/error_log --http-log-path=/var/log/nginx/access_log --pid-path=/var/run/nginx.pid --lock-path=/var/run/nginx.lock --http-client-body-temp-path=/var/cache/nginx/client_temp --http-proxy-temp-path=/var/cache/nginx/proxy_temp --http-fastcgi-temp-path=/var/cache/nginx/fastcgi_temp
--http-uwsgi-temp-path=/var/cache/nginx/uwsgi_temp --http-scgi-temp-path=/var/cache/nginx/scgi_temp --user=nobody --group=nobody --with-http_ssl_module --with-http_realip_module --with-http_addition_module --with-http_sub_module --with-http_dav_module --with-http_flv_module
--with-http_mp4_module --with-http_gunzip_module --with-http_gzip_static_module --with-http_random_index_module --with-http_secure_link_module --with-http_stub_status_module --with-http_auth_request_module --add-dynamic-module=naxsi-http2/naxsi_src --with-file-aio
--with-threads --with-stream --with-stream_ssl_module --with-http_slice_module --with-compat --with-http_v2_module --with-http_geoip_module=dynamic --add-dynamic-module=ngx_pagespeed-1.12.34.2-stable --add-dynamic-module=/usr/local/rvm/gems/ruby-2.4.1/gems/passenger-5.1.8/src/nginx_module
--add-dynamic-module=ngx_brotli --add-dynamic-module=echo-nginx-module-0.60 --add-dynamic-module=headers-more-nginx-module-0.32 --add-dynamic-module=ngx_http_redis-0.3.8 --add-dynamic-module=redis2-nginx-module --add-dynamic-module=srcache-nginx-module-0.31
--add-dynamic-module=ngx_devel_kit-0.3.0 --add-dynamic-module=set-misc-nginx-module-0.31 --add-dynamic-module=testcookie-nginx-module --add-dynamic-module=ModSecurity-nginx --with-cc-opt='-O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector-strong
--param=ssp-buffer-size=4 -grecord-gcc-switches -m64 -mtune=generic' --with-ld-opt=-Wl,-E<o:p></o:p></p>
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<p class="MsoNormal" style="margin-left:36.0pt">#######################<o:p></o:p></p>
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<p class="MsoNormal" style="margin-left:36.0pt"><o:p> </o:p></p>
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<p class="MsoNormal" style="margin-left:36.0pt"><o:p> </o:p></p>
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<p class="MsoNormal" style="margin-left:36.0pt">What could be causing this? The server is quite capable and this happens only rarely<o:p></o:p></p>
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<p class="MsoNormal" style="margin-left:36.0pt"><o:p> </o:p></p>
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<p class="MsoNormal" style="margin-left:36.0pt"><o:p> </o:p></p>
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<p class="MsoNormal" style="margin-left:36.0pt">-- <o:p></o:p></p>
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<p class="MsoNormal" style="margin-left:36.0pt"><b>Anoop P Alias</b> <o:p></o:p></p>
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<p class="MsoNormal" style="margin-left:36.0pt"><o:p> </o:p></p>
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