how to put files in different dirs

hi . Guys i'm designing a django web site,which produce many files. if all these files are in ONE directory。i'm afraid that performance is a problem. even i can put many entries in stattic-dirs in setting.py.but it seems only one entry in stattic-dirs be used Can anyone tell me how i can put

what's different between {% static %} and {{ STATIC_URL}}

hi,guys i'm new to django。when I write my first app, there are 2 options to access static files, 1 using {{ STATIC_URL}} 2 using {% load staticfiles%} then {% static %} what 's different between the 2 options, and ,when I migrate from development to production env which one is conveniency ?