Two domain names are based on the previous project preparation, the recent business needs, the need for secondary extension (example: www.guodong.com/a/ www.guodong.com/b/) in a domain name much gossip that directly on map
Some understanding of Location:
admin.guodong.com/sfaadmin
Project full path: / data / www / ceo / sfaadmin
domain name corresponding to the full path of sfaadmin sfaadmin.
I hope useful to you.