Syslog

http://graylog2.org/

http://fak3r.com/2013/08/22/howto-build-a-simple-log-server-with-splunk-like-features/

http://www.linuxfly.org/post/172/1/1/

http://blog.sina.com.cn/s/blog_9d6a56b10101n7jf.html