What causes a lot of broken links when testing?

Question

PHP

Добрый день,

Кто с таким сталкивался, скажите в чём может быть причина сбросов сервера
 в 100 одновременных потоков?
На старом сервере Apache+Nginx если тестировать сайт в 100 потоков, "битых"
 ссылок примерно в 100 раз меньше, чем на новом в связке Nginx+php-fpm? 
Под битыми ссылками имеется в виду, сервер не ответил на этот запрос в данную
 секунду времени. Если "битую" ссылку открыть в браузере, то работает 
без проблем.

Конфигурационные файлы Nginx:

nginx.conf:
-----------------------------------------------------------------

user  nginx;
worker_processes  4;

error_log  /var/log/nginx/error.log warn;
pid        /var/run/nginx.pid;


events {
    worker_connections  1024;
}


http {
    include       /etc/nginx/mime.types;
    default_type  application/octet-stream;

    log_format  main  '$remote_addr - $remote_user [$time_local] "$request" '
                      '$status $body_bytes_sent "$http_referer" '
                      '"$http_user_agent" "$http_x_forwarded_for"';

    access_log  /var/log/nginx/access.log  main;

    sendfile        on;
    #tcp_nopush     on;

    keepalive_timeout  65;

    #gzip  on;
    
    server_names_hash_bucket_size 10240;
    
    include /etc/nginx/conf.d/*.conf;
}


site.vhost:
-----------------------------------------------------------------

server {
        listen *:80;
        server_name site.com www.site.com;
        root   /var/www/site.com/web;
        index index.php index.html index.htm;

        #location ~ \.shtml$ {
        #    ssi on;
        #}

        error_log /var/log/ispconfig/httpd/site.com/error.log;
        access_log /var/log/ispconfig/httpd/site.com/access.log combined;

        location ~ /\. {
            deny all;
            access_log off;
            log_not_found off;
        }

        location = /favicon.ico {
            log_not_found off;
            access_log off;
        }

        location = /robots.txt {
            allow all;
            log_not_found off;
            access_log off;
        }
        
  # Static Contents
  location ~* ^.+.(jpg|jpeg|gif|png|ico|zip |tgz|gz|rar
|bz2|doc|xls|pdf|ppt |txt|tar|mid|midi|wav|
bmp|rtf)$ {
    access_log off;
    log_not_found off;                
    expires 1y;                
  }
  # CSS and JS
  location ~* ^.+.(css|js)$ {
    access_log off;
    log_not_found off;                
  }
  
  server_tokens off;
  recursive_error_pages off;
  fastcgi_intercept_errors on;
  
  client_max_body_size 20m;
  client_body_buffer_size 128k;

  location ~ \.(tpl|log|sql)$ {deny all; access_log off; log_not_found off; }

# Pass PHP scripts to PHP-FPM
location ~* \.php$ {
    if (!-e $document_root$document_uri){return 404;}
    fastcgi_index   index.php;
    #fastcgi_pass    127.0.0.1:9000;
    fastcgi_pass   unix:/var/lib/php5-fpm/web2.sock;
    include         fastcgi_params;
    fastcgi_param   SCRIPT_FILENAME    $document_root$fastcgi_script_name;
    fastcgi_param   SCRIPT_NAME        $fastcgi_script_name;
  }

  location / {
    
    fastcgi_split_path_info ^(.+\.php)(/.+)$;
    #fastcgi_pass 127.0.0.1:9000;
    fastcgi_pass unix:/var/lib/php5-fpm/web2.sock;
    fastcgi_index index.php;
    fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
    include fastcgi_params;
    fastcgi_read_timeout 900s; # 15 minutes
    
    access_log off;
    
    root /var/www/site.com/web;
  }
}



php-fpm.d/site.conf:
-----------------------------------------------------------------

[site]

listen = /var/lib/php5-fpm/web2.sock
listen.owner = web2
listen.group = client1
listen.mode = 0660

user = web2
group = client1

request_slowlog_timeout = 5s
slowlog = /var/log/php-fpm/slowlog-site.log
listen.allowed_clients = 127.0.0.1

pm = dynamic
pm.max_children = 9
pm.start_servers = 3
pm.min_spare_servers = 2
pm.max_spare_servers = 5
pm.max_requests = 200

listen.backlog = -1
pm.status_path = /status
request_terminate_timeout = 120s
rlimit_files = 131072
rlimit_core = unlimited
catch_workers_output = yes
env[HOSTNAME] = $HOSTNAME

chdir = /

php_admin_value[open_basedir] = /var/www/clients/client1/site
php_admin_value[session.save_path] = /var/www/clients/site/tmp
php_admin_value[upload_tmp_dir] = /var/www/clients/site/tmp

Answer 1

To mine the answer is quite obvious.
you used to use it exclusively as a proxy and it was enough.
Now you have increased the number of simultaneous connections
and uptime.
Increase both values ​​and that's it.

Answer 2

Set fpm to a port, not a socket. It's strange, but this way it works more stable under heavy loads and a large number of requests.
It is also not recommended to use pm = dynamic for highload. It is better to calculate the approximate number of workers depending on the loads.

Answer 3

You can also use the php-fpm pool, in case one of them falls out

upstream php {
    server unix:/var/run/php5-fpm.s0.sock;
    server unix:/var/run/php5-fpm.s1.sock;
}

location ~ \.php$ {
    fastcgi_pass php;