nginx缓存加速

简介

Nginx支持类似Squid的缓存功能
把URL以及相关信息当成key，用MD5编码哈希后，把数据文件保存在硬盘上。只能为指定的URL或者状态码设置过期时间，并不支持类似squid的purge命令来手动清除指定缓存页面。

可通过第三方的ngx_cache_purge来清除指定的URL缓存。

Nginx的缓存加速功能是由proxy_cache和fastcgi_cache两个功能模块完成的。

Nginx缓存加速特点
缓存功能也十分稳定，运行速度不逊于squid，对多核CPU的利用率比其他的开源软件也要好，支持高并发请求数，能同时承受更多的访问请求。

Nginx缓存实验

服务器准备：
nginx：192.168.1.10
web：192.168.1.11

下载缓存所需要的包
wget http://labs.frickle.com/files/ngx_cache_purge-2.3.tar.gz
nginx-1.6自行下载

安装
useradd -M -s /sbin/nologin nginx
yum -y install pcre-devel zlib-devel
tar xf ngx_cache_purge-2.3.tar.gz -C /usr/src/
tar xf nginx-1.6.0.tar.gz -C /usr/src/
cd /usr/src/nginx-1.6.0/
./configure --prefix=/usr/local/nginx --user=nginx --group=nginx --with-http_stub_status_module --with-pcre --add-module=/usr/src/ngx_cache_purge-2.3/ && make && make install

/usr/local/nginx/sbin/nginx -V 查看模块是否加载

ln -s /usr/local/nginx/sbin/nginx /usr/local/sbin/
cd /usr/local/nginx/

配置文件

vim /usr/local/nginx/conf/nginx.conf

user  nginx nginx;
worker_processes  1;

error_log  logs/error.log crit;
#error_log  logs/error.log  notice;
#error_log  logs/error.log  info;

pid        logs/nginx.pid;

worker_rlimit_nofile 65535;

events {
    use epoll;
    worker_connections  65535;
}


http {
    include       mime.types;
    default_type  application/octet-stream;
    charset utf-8;
    #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  logs/access.log  main;

    sendfile        on;
    tcp_nopush     on;

    #keepalive_timeout  0;
    keepalive_timeout  65;

    #gzip  on;
    tcp_nodelay on;
    client_body_buffer_size 512k;
    proxy_connect_timeout 5;
    proxy_read_timeout 60;
    proxy_send_timeout 5;
    proxy_buffer_size 16k; 
    proxy_buffers 4 64k;
    proxy_busy_buffers_size 128k;
    proxy_temp_file_write_size 128k;
    proxy_temp_path /var/cache/nginx/cache_temp;
    proxy_cache_path /var/cache/nginx/proxy_cache levels=1:2 keys_zone=cache_one:200m inactive=1d max_size=30g; 

    upstream backend_server {
    server 192.168.1.11:80 weight=1 max_fails=2 fail_timeout=30s;
    }

    server {
        listen       80;
        server_name  www.amber.com 192.168.1.10;
        index  index.html index.htm;

        location / {
	    proxy_next_upstream http_502 http_504 error timeout invalid_header;
 	    proxy_cache cache_one;
	    proxy_cache_valid 200 304 12h;
	    proxy_cache_key $host$uri$is_args$args;
	    proxy_set_header Host $host;
	    proxy_set_header X-Forwarded-For $remote_addr;
	    proxy_pass http://backend_server;
	    expires 1d;
        }

        location ~ /purge(/.*) {
	    allow 127.0.0.1;
	    allow 192.168.1.0/24;
	    deny all;
	    proxy_cache_purge cache_one $host$1$is_args$args;
	}

        location ~ .*.(php|jsp|cgi)?$ {
		 proxy_set_header Host $host;
		 proxy_set_header X-Forwarded-For $remote_addr;
		 proxy_pass http://backend_server;
	}
	access_log off;
    }
}

详解：

创建缓存目录：

mkdir /var/cache/nginx
ulimit -SHn 65535
nginx -t
ll /var/cache/nginx/

测试：

nginx
netstat -anpt |grep 80
安装Web服务器，建立测试页
yum -y install httpd
sed -n '276p' /etc/httpd/conf/httpd.conf
systemctl start httpd
netstat -anpt |grep 80
查看缓存目录
ll /var/cache/nginx/proxy_cache/