版本
Centos版本：6.5
Apache版本：2.2.15
步骤
1、进入/etc/httpd/conf下打开httpd.conf文件
开启Gzip压缩功能，即去掉LoadModule deflate_module modules/mod_deflate.so这行前面的#号，默认已经去掉。
2、进行Gzip压缩设置，添加：
# mod_deflate：
<ifmodule mod_deflate.c>
DeflateCompressionLevel
AddOutputFilterByType DEFLATE text/plain
AddOutputFilterByType DEFLATE text/html
AddOutputFilterByType DEFLATE text/xml
AddOutputFilterByType DEFLATE text/css
AddOutputFilterByType DEFLATE text/javascript
AddOutputFilterByType DEFLATE application/xhtml+xml
AddOutputFilterByType DEFLATE application/xml
AddOutputFilterByType DEFLATE application/rss+xml
AddOutputFilterByType DEFLATE application/atom_xml
AddOutputFilterByType DEFLATE application/x-javascript
AddOutputFilterByType DEFLATE application/x-httpd-php
AddOutputFilterByType DEFLATE image/svg+xml
</ifmodule>
其中DeflateCompressionLevel 6为压缩率，取值1-9之间，默认为6.
3、重启apache
service httpd restart
4、如果网站使用的是CodeIgniter框架，需要在config文件中进行设置，将
$config['compress_output'] = FALSE;
改为：
$config['compress_output'] = TRUE;