nginx高并发优化——轻松应对1万并发

测试机器512M内存，swap分区407M ，centos6.5，nginx1.10.1，php5.6
默认的Linux内核参数和nginx参数考虑的是最通用场景，不适合高并发
所以优化思路主要包括两个层面：系统层面+nginx层面


一、系统层面
1、调整同时打开文件数量
ulimit -n 20480
2、TCP最大连接数（somaxconn）
echo 10000 > /proc/sys/net/core/somaxconn
3、TCP连接立即回收、回用（recycle、reuse）
echo 1 > /proc/sys/net/ipv4/tcp_tw_reuse
echo 1 > /proc/sys/net/ipv4/tcp_tw_recycle
4、不做TCP洪水抵御
echo 0 > /proc/sys/net/ipv4/tcp_syncookies
也可以直接使用优化后的配置，在/etc/sysctl.conf中加入：
net.core.somaxconn = 20480
net.core.rmem_default = 262144
net.core.wmem_default = 262144
net.core.rmem_max = 16777216
net.core.wmem_max = 16777216
net.ipv4.tcp_rmem = 4096 4096 16777216
net.ipv4.tcp_wmem = 4096 4096 16777216
net.ipv4.tcp_mem = 786432 2097152 3145728
net.ipv4.tcp_max_syn_backlog = 16384
net.core.netdev_max_backlog = 20000
net.ipv4.tcp_fin_timeout = 15
net.ipv4.tcp_max_syn_backlog = 16384
net.ipv4.tcp_tw_reuse = 1
net.ipv4.tcp_tw_recycle = 1
net.ipv4.tcp_max_orphans = 131072
net.ipv4.tcp_syncookies = 0
使用：sysctl -p 生效
sysctl -p


二、nginx层面
修改nginx配置文件，nginx.conf
增加work_rlimit_nofile和worker_connections数量，并禁用keepalive_timeout。
worker_processes  1; #nginx 进程数，建议按照cpu 数目来指定，一般为它的倍数
worker_rlimit_nofile 20000; #一个nginx 进程打开的最多文件描述符数目，理论值应该是最多打开文件数（ulimit -n）与nginx 进程数相除，但是nginx 分配请求并不是那么均匀，所以最好与ulimit -n 的值保持一致
events {
use epoll;#使用epoll的I/O模型
worker_connections 20000;#每个进程允许的最多连接数， 理论上每台nginx 服务器的最大连接数为worker_processes*worker_connections
multi_accept on;
}
http {
keepalive_timeout 0;
}


三、测试
重启nginx
service nginx restart


使用ab压力测试

D:\phpStudy\Apache\bin>ab -r -n 150000  -c 10000 http://192.168.1.198/msg.phpThis is ApacheBench, Version 2.3 <$Revision: 1706008 $>Copyright 1996 Adam Twiss, Zeus Technology Ltd, http://www.zeustech.net/Licensed to The Apache Software Foundation, http://www.apache.org/Benchmarking 192.168.1.198 (be patient)Completed 15000 requestsCompleted 30000 requestsCompleted 45000 requestsCompleted 60000 requestsCompleted 75000 requestsCompleted 90000 requestsCompleted 105000 requestsCompleted 120000 requestsCompleted 135000 requestsCompleted 150000 requestsFinished 150000 requestsServer Software:        nginx/1.10.1Server Hostname:        192.168.1.198Server Port:            80Document Path:          /msg.phpDocument Length:        955 bytesConcurrency Level:      10000Time taken for tests:   553.886 secondsComplete requests:      150000Failed requests:        74065   (Connect: 0, Receive: 0, Length: 74065, Exceptions: 0)Non-2xx responses:      74065Total transferred:      108769526 bytesHTML transferred:       85048014 bytesRequests per second:    270.81 [#/sec] (mean)Time per request:       36925.756 [ms] (mean)Time per request:       3.693 [ms] (mean, across all concurrent requests)Transfer rate:          191.77 [Kbytes/sec] receivedConnection Times (ms)              min  mean[+/-sd] median   maxConnect:        0    1  19.0      1    3004Processing:   332 33370 25597.6  31689   92093Waiting:      163 32879 25640.0  31420   91598Total:        332 33370 25597.5  31689   92093Percentage of the requests served within a certain time (ms)  50%  31689  66%  60464  75%  60730  80%  60928  90%  61319  95%  61790  98%  62191  99%  62640 100%  92093 (longest request)D:\phpStudy\Apache\bin>

如果不优化，运行时间超过半个小时！！！

ab -r -n 150000  -c 10000 http://192.168.1.198/msg.phpThis is ApacheBench, Version 2.3 <$Revision: 1706008 $>Copyright 1996 Adam Twiss, Zeus Technology Ltd, http://www.zeustech.net/Licensed to The Apache Software Foundation, http://www.apache.org/Benchmarking 192.168.1.198 (be patient)Completed 15000 requestsCompleted 30000 requestsCompleted 45000 requestsCompleted 60000 requestsCompleted 75000 requestsCompleted 90000 requestsCompleted 105000 requestsCompleted 120000 requestsCompleted 135000 requestsCompleted 150000 requestsFinished 150000 requestsServer Software:        nginx/1.10.1Server Hostname:        192.168.1.198Server Port:            80Document Path:          /msg.phpDocument Length:        955 bytesConcurrency Level:      10000Time taken for tests:   3136.477 secondsComplete requests:      150000Failed requests:        0Total transferred:      168150000 bytesHTML transferred:       143250000 bytesRequests per second:    47.82 [#/sec] (mean)Time per request:       209098.485 [ms] (mean)Time per request:       20.910 [ms] (mean, across all concurrent requests)Transfer rate:          52.35 [Kbytes/sec] receivedConnection Times (ms)              min  mean[+/-sd] median   maxConnect:        0   20 236.9      1    3045Processing:  4178 202109 29524.0 208780  220830Waiting:     1246 105285 59956.2 104752  216204Total:       4179 202129 29523.9 208806  220831Percentage of the requests served within a certain time (ms)  50%  208806  66%  210991  75%  211892  80%  212733  90%  213611  95%  214917  98%  217376  99%  217451 100%  220831 (longest request)