Too many connections in waiting state

[Lucas Rolff]

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.

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.

Best Regards,

From: nginx <nginx-bounces at nginx.org> on behalf of Anoop Alias <anoopalias01 at gmail.com>
Reply-To: "nginx at nginx.org" <nginx at nginx.org>
Date: Thursday, 7 September 2017 at 11.52
To: Nginx <nginx at nginx.org>
Subject: Too many connections in waiting state

Hi,

I see sometimes too many waiting connections on nginx .

This often gets cleared on a restart , but otherwise pileup

###################
Active connections: 4930
server accepts handled requests
 442071 442071 584163
Reading: 2 Writing: 539 Waiting: 4420
#######################
[root at web1 ~]# grep keep /etc/nginx/conf.d/http_settings_custom.conf
keepalive_timeout               10s;
keepalive_requests              200;
keepalive_disable               msie6 safari;
########################

[root at web1 ~]# nginx -V
nginx version: nginx/1.13.3
built by gcc 4.8.5 20150623 (Red Hat 4.8.5-11) (GCC)
built with LibreSSL 2.5.5
TLS SNI support enabled
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
#######################


What could be causing this? The server is quite capable and this happens only rarely


--
Anoop P Alias

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