http://www.cyberciti.biz/tips/top-linux-monitoring-tools.html
http://fred.oracle1.com/weblog/2010/07/07/6%E4%B8%AAlinux%E6%80%A7%E8%83%BD%E7%9B%91%E6%8E%A7%E5%91%BD%E4%BB%A4%E8%A1%8C%E5%B7%A5%E5%85%B7/