基于Apache mod_proxy的反向代理缓存加速实现
Apache包含了mod_proxy模块，可以用来实现代理服务器，针对后台服务器的反向加速
安装apache 1.3.x 编译时：
--enable-shared=max --enable-module=most
注：Apache 2.x中mod_proxy已经被分离成mod_proxy和mod_cache：同时mod_cache有基于文件和基于内存的不同实现
创建/var/www/proxy，设置apache服务所用户可写
mod_proxy配置样例：反相代理缓存＋缓存
架设前台的www.example.com反向代理后台的www.backend.com的8080端口服务。
修改：httpd.conf
<VirtualHost *
ServerName www.example.com
ServerAdmin admin@example.com
# reverse proxy setting
ProxyPass / http://www.backend.com:8080/
ProxyPassReverse / http://www.backend.com:8080/
# cache dir root
CacheRoot "/var/www/proxy"
# max cache storage
CacheSize 50000000
# hour: every 4 hour
CacheGcInterval 4
# max page expire time: hour
CacheMaxExpire 240
# Expire time = (now - last_modified) * CacheLastModifiedFactor
CacheLastModifiedFactor 0.1
# defalt expire tag: hour
CacheDefaultExpire 1
# force complete after precent of content retrived: 60-90%
CacheForceCompletion 80
CustomLog /usr/local/apache/logs/dev_access_log combined
</VirtualHost
基于Squid的反向代理加速实现
Squid是一个更专用的代理服务器，性能和效率会比Apache的mod_proxy高很多。
如果需要combined格式日志补丁：
http://www.squid-cache.org/mail-archive/squid-dev/200301/0164.html
squid的编译：
./configure --enable-useragent-log
--enable-referer-log --enable-default-err-language=Simplify_Chinese --enable-err-languages="Simplify_Chinese English" --disable-internal-dns
make
#make install
#cd /usr/local/squid
make dir cache
chown squid.squid *
vi /usr/local/squid/etc/squid.conf
在/etc/hosts中：加入内部的DNS解析，比如：
192.168.0.4 www.chedong.com
192.168.0.4 news.chedong.com
192.168.0.3 bbs.chedong.com
---------------------cut here----------------------------------
# visible name
visible_hostname cache.example.com
# cache config: space use 1G and memory use 256M
cache_dir ufs /usr/local/squid/cache 1024 16 256
cache_mem 256 MB
cache_effective_user squid
cache_effective_group squid
http_port 80
httpd_accel_host virtual
httpd_accel_single_host off
httpd_accel_port 80
httpd_accel_uses_host_header on
httpd_accel_with_proxy on
# accelerater my domain only
acl acceleratedHostA dstdomain .example1.com
acl acceleratedHostB dstdomain .example2.com
acl acceleratedHostC dstdomain .example3.com
# accelerater http protocol on port 80
acl acceleratedProtocol protocol HTTP
acl acceleratedPort port 80
# access arc
acl all src 0.0.0.0/0.0.0.0
# Allow requests when they are to the accelerated machine AND to the
# right port with right protocol
http_access allow acceleratedProtocol acceleratedPort acceleratedHostA
http_access allow acceleratedProtocol acceleratedPort acceleratedHostB
http_access allow acceleratedProtocol acceleratedPort acceleratedHostC
# logging
emulate_httpd_log on
cache_store_log none
# manager
acl manager proto cache_object
http_access allow manager all
cachemgr_passwd pass all
----------------------cut here---------------------------------
创建缓存目录：
/usr/local/squid/sbin/squid -z
启动squid
/usr/local/squid/sbin/squid
停止squid：
/usr/local/squid/sbin/squid -k shutdown
启用新配置：
/usr/local/squid/sbin/squid -k reconfig
通过crontab每天0点截断/轮循日志：
0 0 * * * (/usr/local/squid/sbin/squid -k rotate)
附：SQUID性能测试试验
phpMan.php是一个基于php的man page server，每个man
page需要调用后台的man命令和很多页面格式化工具，系统负载比较高，提供了Cache
Friendly的URL，以下是针对同样的页面的性能测试资料：
测试环境：Redhat 8 on Cyrix 266 / 192M Mem
测试程序：使用apache的ab(apache benchmark)：
测试条件：请求50次，并发50个连接
测试项目：直接通过apache 1.3 (80端口) vs squid 2.5(8000端口：加速80端口)
测试1：无CACHE的80端口动态输出：
ab -n 100 -c 10 http://www.chedong.com:81/phpMan.php/man/kill/1
This is ApacheBench, Version 1.3d <$Revision: 1.2 $ apache-1.3
Copyright (c) 1996 Adam Twiss, Zeus Technology Ltd,
Copyright (c) 1998-2001 The Apache Group, http://www.apache.org/
Benchmarking localhost (be patient).....done
Server Software:
Apache/1.3.23
Server Hostname:
localhost
Server
Port:
80
Document Path:
/phpMan.php/man/kill/1
Document Length:
4655 bytes
Concurrency Level:
5
Time taken for tests:
63.164 seconds
Complete requests:
50
Failed requests:
0
Broken pipe errors:
0
Total transferred:
245900 bytes
HTML transferred:
232750 bytes
Requests per second:
0.79 [#/sec] (mean)
Time per request:
6316.40 [ms]
(mean)
Time per request:
1263.28 [ms]
(mean, across all concurrent requests)
Transfer rate:
3.89 [Kbytes/sec] received
Connnection Times (ms)
min
mean[+/-sd] median
max
Connect:
0
29
106.1
0
553
Processing:
2942
6016
1845.4
6227 10796
Waiting:
2941
5999 1850.7
6226 10795
Total:
2942
6045 1825.9
6227 10796
Percentage of the requests served within a certain time (ms)
50%
6227
66%
7069
75%
7190
80%
7474
90%
8195
95%
8898
98%
9721
99%
10796
100%
10796 (last request)
测试2：SQUID缓存输出
/home/apache/bin/ab -n50 -c5
"http://localhost:8000/phpMan.php/man/kill/1"
This is ApacheBench, Version 1.3d <$Revision: 1.2 $ apache-1.3
Copyright (c) 1996 Adam Twiss, Zeus Technology Ltd,
Copyright (c) 1998-2001 The Apache Group, http://www.apache.org/
Benchmarking localhost (be patient).....done
Server Software:
Apache/1.3.23
Server Hostname:
localhost
Server
Port:
8000
Document Path:
/phpMan.php/man/kill/1
Document Length:
4655 bytes
Concurrency Level:
5
Time taken for tests:
4.265 seconds
Complete requests:
50
Failed requests:
0
Broken pipe errors:
0
Total transferred:
248043 bytes
HTML transferred:
232750 bytes
Requests per second:
11.72 [#/sec] (mean)
Time per request:
426.50 [ms] (mean)
Time per request:
85.30 [ms] (mean,
across all concurrent requests)
Transfer rate:
58.16 [Kbytes/sec] received
Connnection Times (ms)
min
mean[+/-sd] median
max
Connect:
0
1
9.5
0
68
Processing:
7
83
537.4
7
3808
Waiting:
5
81
529.1
6
3748
Total:
7
84
547.0
7
3876
Perce
