随着网站访问人数越来越多，承受的并发和压力也越来越高，这时候我们需要对网站和架构进行优化，今天我们来讨论使用Squid对架构进行优化，缓存网站。网上对squid描述的文章也有成千上万，我这里简单记录一下实践的步骤。
一、实施环境
系统版本：CentOSx86_64 5.8
Squid版本：squid-2.6
Nginx版本：nginx-1.4.2
二、正式安装
安装之前我们需要对系统进行优化，主要优化系统内核相关参数，仅供参考：
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#sysctl.conf config 2014-03-26 net.ipv4.ip_forward = 0 net.ipv4.conf.default.rp_filter = 1 net.ipv4.conf.default.accept_source_route = 0 kernel.sysrq = 0 kernel.core_uses_pid = 1 net.ipv4.tcp_syncookies = 1 kernel.msgmnb = 65536 kernel.msgmax = 65536 kernel.shmmax = 68719476736 kernel.shmall = 4294967296 net.ipv4.tcp_max_tw_buckets = 10000 net.ipv4.tcp_sack = 1 net.ipv4.tcp_window_scaling = 1 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.netdev_max_backlog = 262144 net.core.somaxconn = 262144 net.ipv4.tcp_max_orphans = 3276800 net.ipv4.tcp_max_syn_backlog = 262144 net.ipv4.tcp_timestamps = 0 net.ipv4.tcp_synack_retries = 1 net.ipv4.tcp_syn_retries = 1 net.ipv4.tcp_tw_recycle = 1 net.ipv4.tcp_tw_reuse = 1 net.ipv4.tcp_mem = 94500000 915000000 927000000 net.ipv4.tcp_fin_timeout = 1 net.ipv4.tcp_keepalive_time = 15 net.ipv4.ip_local_port_range = 1024 65535
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接下来上自动安装Squid脚本，里面分别配置了两个虚拟主机域名，前端有LVS，LVS均衡后端多组squid集群，根据命中率去调整squid集群的数量，Squid后端均衡Nginx或者Apache。（完整的架构LVS+Keepalived+Squid+Nginx+Resin/Tomcat/PHP+MySQL集群）
简单逻辑图如下：
直接上脚本：
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#!/bin/sh #Auto make install squid server #Author wugk 2014-03-26 SQUID_CNF=/etc/squid/squid.conf CACHE_DIR=( /data/cache1 /data/cache2 ) #Install squid shell yum install -y squid #config squid.conf cat >>$SQUID_CNF <<EOF #global config squid.conf 2014-03-26 http_port 80 accel vhost vport cache_peer 192.168.149.128 parent 80 0 originserver name=wugk1 cache_peer 192.168.149.129 parent 80 0 originserver name=wugk2 cache_peer_domain wugk1 www.wugk1.com cache_peer_domain wugk2 www.wugk2.com visible_hostname localhost forwarded_for off via off cache_vary on #acl config acl manager proto cache_object acl localhost src 127.0.0.1/32 acl to_localhost dst 127.0.0.0/8 0.0.0.0/32 acl localnet src 10.0.0.0/8 # RFC1918 possible internal network acl localnet src 172.16.0.0/12 # RFC1918 possible internal network acl localnet src 192.168.0.0/16 # RFC1918 possible internal network acl SSL_ports port 443 acl Safe_ports port 80 8080 # http acl Safe_ports port 21 # ftp acl Safe_ports port 443 # https acl all src 0.0.0.0/0 acl CONNECT method CONNECT http_access allow manager localhost http_access deny manager http_access deny !Safe_ports http_access deny CONNECT !SSL_ports http_access allow localnet http_access allow localhost http_access allow all acl PURGE method PURGE http_access allow PURGE localhost http_access deny PURGE #squid config 2014-03-25 cache_dir aufs /data/cache1 10240 16 256 cache_dir aufs /data/cache2 10240 16 256 cache_mem 4000 MB maximum_object_size 8 MB maximum_object_size_in_memory 256 KB hierarchy_stoplist cgi-bin ? coredump_dir /var/spool/squid refresh_pattern ^ftp: 1440 20% 10080 refresh_pattern ^gopher: 1440 0% 1440 refresh_pattern -i (/cgi-bin/|\?) 0 0% 0 refresh_pattern \.(jpg|png|gif|mp3|xml|html|htm|css|js) 1440 50% 2880 ignore-reload refresh_pattern . 0 20% 4320 EOF #config cache_dir mkdir -p ${CACHE_DIR[@]} ;chown -R squid:squid ${CACHE_DIR[@]} #restart squid server /etc/init.d/squid restart if [ "$?" == "0" ];then echo "The Squid Server Install Successfully !!" else echo "The Squid Server Install Failed !!,Please Check Log......" fi
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***测试，前端LVS截图（注LVS此处不配置了，博客有专门的安装方法）
通过浏览器查看head头，缓存命中情况截图如下：
通过命令
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squidclient -p 80 mgr:info |egrep "(Request Hit Ratios|Byte Hit Ratios)"
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查看缓存命中率如下：
三、批量清空缓存
使用Shell脚本批量清空squid缓存脚本auto_clean_cache.sh
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#!/bin/sh DIR=/data/cache/ Command=/usr/sbin/squidclient if [ "$1" = "" ];then echo "Usage:{$0 "\$1" ,Example exec $0 forum.php}" exit fi grep -r -a $1 ${DIR} | strings | grep "http:"|grep -v "=" >list.txt count=`cat list.txt|wc -l` if [ "$count" -eq "0" ];then echo -e "---------------------------------\nThe $1 cache already update,Please exit ......" exit fi while read line do $Command -m PURGE -p 80 "$line" >>/dev/null if [ $? -eq 0 ];then echo -e "----------------------------------\nThe $line cache update successfully!" fi done < list.txt
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脚本执行：
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[root@node2 ~]# sh auto_clean_cache.sh forum.php ---------------------------------- The http://www.wugk2.com/forum.php cache update successfully! [root@node2 ~]#
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更多squid优化及深入配置后期更新。