今天网站出现负载很大，cpu占用率超高，网站延迟很大，前台出现此错误信息：
[19-Sep-2016 23:30:38] WARNING: [pool www] child 31954, script '/var/www/html/casino.21pink.com/public/index.php' (request: "POST /index.php") executing too slow (2.407095 sec), logging
[19-Sep-2016 23:30:38] WARNING: [pool www] child 31943, script '/var/www/html/casino.21pink.com/public/index.php' (request: "POST /index.php") executing too slow (2.062648 sec), logging
[19-Sep-2016 23:30:38] WARNING: [pool www] child 31941, script '/var/www/html/casino.21pink.com/public/index.php' (request: "POST /index.php") executing too slow (2.666022 sec), logging
[19-Sep-2016 23:30:38] WARNING: [pool www] child 30382, script '/var/www/html/casino.21pink.com/public/index.php' (request: "POST /index.php") executing too slow (2.021010 sec), logging
[19-Sep-2016 23:30:38] WARNING: [pool www] child 29797, script '/var/www/html/casino.21pink.com/public/index.php' (request: "POST /index.php") executing too slow (2.554333 sec), logging
[19-Sep-2016 23:39:27] WARNING: [pool www] seems busy (you may need to increase pm.start_servers, or pm.min/max_spare_servers), spawning 8 children, there are 2 idle, and 68 total children
[19-Sep-2016 23:40:58] WARNING: [pool www] seems busy (you may need to increase pm.start_servers, or pm.min/max_spare_servers), spawning 8 children, there are 0 idle, and 81 total children
[19-Sep-2016 23:40:59] WARNING: [pool www] seems busy (you may need to increase pm.start_servers, or pm.min/max_spare_servers), spawning 16 children, there are 3 idle, and 86 total children
[19-Sep-2016 23:41:00] WARNING: [pool www] seems busy (you may need to increase pm.start_servers, or pm.min/max_spare_servers), spawning 32 children, there are 2 idle, and 88 total children
[19-Sep-2016 23:41:01] WARNING: [pool www] seems busy (you may need to increase pm.start_servers, or pm.min/max_spare_servers), spawning 32 children, there are 0 idle, and 91 total children
从信息看，应该是php进程较少：
经过查看发现进程确实很少，解决如下：
修改配置文件增加进程
vim /usr/local/php/etc/php-fpm.ini
pm = dynamic #动态模式
pm.max_children = 512 #静态开启的进程数
pm.start_servers = 128 #动态模式的起始进程数
pm.min_spare_servers = 128 #动态模式最小进程数
pm.max_spare_servers = 512 #动态模式最大进程数
数值设置，参考自己的实际硬件配置，可以参考 内存/20M 来计算。
重新加载进程
/etc/init.d/php-fpm reload
等待了一点时间发现又报错：
[19-Sep-2016 23:30:20] WARNING: [pool www] child 7782, script '/var/www/html/casino.21pink.com/public/index.php' (request: "POST /index.php") executing too slow (2.224150 sec), logging
[19-Sep-2016 23:30:08] ERROR: failed to ptrace(PEEKDATA) pid 7663: Input/output error (5)
[19-Sep-2016 23:30:20] WARNING: [pool www] child 31952, script '/var/www/html/casino.21pink.com/public/index.php' (request: "POST /index.php") executing too slow (2.045803 sec), logging
[19-Sep-2016 23:30:20] ERROR: failed to ptrace(PEEKDATA) pid 31952: Input/output error (5)
查找资料如下：
It usrears you have request_slowlog_timeout enabled.
This normally takes any request longer than N seconds, logs that it was
taking a long time, then logs a stack trace of the script so you can see
what it was doing that was taking so long.
In your
case, the stack trace (to determine what the script is doing) is
failing. If you're running out of processes, it is because either:
After php-fpm stops the process to trace it, the process fails to resume because of the error tracing it
The process is resuming but continues to run forever.
My first guess would be to disable request_slowlog_timeout.
Since it's not working right, it may be doing more harm than good. If
this doesn't fix the issue of running out of processes, then set the
php.ini max_execution_time to something that will kill the script for sure.
大概说是设置了slowlog和php的最大执行时间。
解决：
禁止slowlog
vim php-fpm.conf
;request_slowlog_timeout = 10s
;slowlog = /usr/local/log/php-fpm/ckl-slow.log
修改最大执行时间：
vim php.ini
max_execution_time = 60
重启进程：
/etc/init.d/php-fpm reload
等待一段时间，发现一切正常。
查看TCP连接相关：
[root@GreenZonewebapp2 php-fpm.d]# ss -s
Total: 323 (kernel 675)
TCP: 4538 (estab 12, closed 4518, orphaned 0, synrecv 0, timewait 4518/0), ports 0
Transport Total IP IPv6
* 675 - -
RAW 0 0 0
UDP 5 4 1
TCP 20 19 1
INET 25 23 2
FRAG 0 0 0
同时发现系统TIMEWAIT 较多，所以优化了一些内核相关参数
#vim /etc/sysctl.conf 进行内核的相关优化
# sysct -p
bash: sysct: command not found
[root@sapi etc]# sysctl -p
net.ipv4.ip_forward = 0
net.ipv4.conf.default.rp_filter = 1
net.ipv4.conf.default.accept_source_route = 0
net.ipv4.tcp_max_tw_buckets = 6000
net.ipv4.ip_local_port_range = 1024 65000
net.ipv4.tcp_tw_recycle = 1
net.ipv4.tcp_tw_reuse = 1
net.ipv4.tcp_syncookies = 1
net.ipv4.tcp_max_orphans = 262144
net.ipv4.tcp_keepalive_time = 1200
net.ipv4.tcp_keepalive_intvl = 30
net.ipv4.tcp_keepalive_probes = 3
net.ipv4.tcp_synack_retries = 1
net.ipv4.tcp_syn_retries = 2
net.ipv4.tcp_max_orphans = 262144
net.ipv4.tcp_max_syn_backlog = 262144
net.ipv4.tcp_timestamps = 0
net.core.rmem_max = 16777216
net.core.wmem_max = 16777216
net.ipv4.tcp_rmem = 4096 87380 4194304
net.ipv4.tcp_wmem = 4096 16384 4194304
net.core.wmem_default = 8388608
net.core.rmem_default = 8388608
net.core.rmem_max = 16777216
net.core.wmem_max = 16777216
net.core.somaxconn = 262144
kernel.sysrq = 0
kernel.core_uses_pid = 1
kernel.msgmnb = 65536
kernel.msgmax = 65536
kernel.shmmax = 68719476736
kernel.shmall = 4294967296
vm.swappiness = 0
fs.file-max = 409600
过一阵再查看：
# ss -s
Total: 281 (kernel 362)
TCP: 520 (estab 22, closed 493, orphaned 0, synrecv 0, timewait 493/0), ports 475
Transport Total IP IPv6
* 362 - -
RAW 0 0 0
UDP 1 1 0
TCP 27 27 0
INET 28 28 0
FRAG 0 0 0