查看apache 进程数：
ps -ef|grep httpd|wc

编辑
/etc/httpd/conf/extra/httpd-mpm.conf

更新版本
cd /usr/local/directadmin/custombuild
./build update
./build clean
./build all d

http://www.directadmin.com/forum/showthread.php?t=29824&page=1

限制连接数组件：
http://dominia.org/djao/limitipconn2.html