我对主题有一些错误。服务器负载不高：~15% CPU，有几 Gb 内存，硬盘不忙。但是大约 3% 的情况下会抛出错误 502。
程序：Debian 6、nginx/0.7.62、php5-fpm (5.3.3-1)。
在 nginx 的 error.log 中是这个错误：
connect() to unix:/var/run/php5-fpm.sock failed
php5-fpm 的状态通常是这样的：
accepted conn: 41680
pool: www
process manager: dynamic
idle processes: 258
active processes: 1
total processes: 259
我认为，这意味着加载并不高。
我增加了积压参数：在 sysctl - net.core.somaxconn = 5000，在 php-fpm 池 - listen.backlog = 5000。没有效果。
我引用一个配置：
/etc/nginx/nginx.conf
user www-data;
worker_processes 8;
timer_resolution 100ms;
worker_rlimit_nofile 20240;
worker_priority -5;
error_log /var/log/nginx/error.log;
pid /var/run/nginx.pid;
events {
worker_connections 2048;
use epoll;
# multi_accept on;
}
http {
include /etc/nginx/mime.types;
access_log /var/log/nginx/access.log;
sendfile on;
tcp_nopush on;
#keepalive_timeout 0;
keepalive_timeout 65;
tcp_nodelay on;
gzip on;
gzip_min_length 1100;
gzip_buffers 64 8k;
gzip_comp_level 3;
gzip_http_version 1.1;
gzip_proxied any;
gzip_types text/plain application/xml application/x-javascript text/css;
gzip_disable "MSIE [1-6]\.(?!.*SV1)";
include /etc/nginx/conf.d/*.conf;
include /etc/nginx/sites-enabled/*;
client_max_body_size 100M;
server_tokens off;
}
/etc/nginx/php_location
fastcgi_pass unix:/var/run/php5-fpm.sock;
fastcgi_index index.php;
fastcgi_param SCRIPT_FILENAME $document_root/$fastcgi_script_name;
fastcgi_buffers 256 128k;
#fastcgi_buffer_size 16k;
#fastcgi_busy_buffers_size 256k;
fastcgi_connect_timeout 300s;
fastcgi_send_timeout 300s;
fastcgi_read_timeout 300s;
include fastcgi_params;
php-fpm 池
[www]
listen = /var/run/php5-fpm.sock
listen.backlog = 5000
listen.owner = www-data
listen.group = www-data
listen.mode = 0666
user = www-data
group = www-data
pm = dynamic
pm.max_children = 1024
pm.start_servers = 64
pm.min_spare_servers = 64
pm.max_spare_servers = 128
pm.max_requests = 32000
pm.status_path = /system/php5-fpm-status
slowlog = /var/www/log/php-fpm.log.slow
chdir = /var/www
我可以做些什么来优化这个系统并使它使用所有服务器资源？
PS。对不起，我的英语很差。