查了Nginx的错误日志为：
2014/08/02 16:14:31 [error] 17029#0: *17941 recv() failed (104: Connection reset by peer) while reading response header from upstream, client: 210.61.12.2, server: blog.lixiphp.com, request: “POST /api/1.0 HTTP/1.1″, upstream: “fastcgi://127.0.0.1:9000″, host: “blog.lixiphp.com” 2014/08/02 16:24:52 [error] 29615#0: *3 recv() failed (104: Connection reset by peer) while reading response header from upstream, client: 58.220.197.35, server: blog.lixiphp.com, request: “GET /404 HTTP/1.1″, upstream: “fastcgi://127.0.0.1:9000″, host: “blog.lixiphp.com”
不要使用php-fpm的request_terminate_timeout， 最好设成request_terminate_timeout=0;
vi /etc/php-fpm.d/www.conf (默认：/usr/local/php/etc/php-fpm.conf)
修改为：
; The timeout for serving a single request after which the worker process will
; be killed. This option should be used when the ‘max_execution_time’ ini option
; does not stop script execution for some reason. A value of ’0′ means ‘off’.
; Available units: s(econds)(default), m(inutes), h(ours), or d(ays)
; Default Value: 0
request_terminate_timeout = 0
因为这个参数会直接杀掉php进程，然后重启php进程，这样前端nginx就会返回104: Connection reset by peer。这个过程是很慢，总体感觉就是网站很卡。
重启 php-fpm 和 Nginx 一切正常。
service nginx restart （/usr/local/nginx/sbin/nginx -s stop;/usr/local/nginx/sbin/nginx;）
killall php-fpm （pkill -9 php）
php-fpm （/etc/init.d/php-fpm）
再打开就OK了。