[OS X TeX] backing up /usr (and MacTeX)

[Alex Hamann]

Hi and sorry for the slightly OT question:
can anybody tell me how the /usr directory and its subdirectories are  
integrated into the overall system structure? Let me illustrate to  
make myself clear: I a probably running into complete re-installation  
because of disk problems and was wondering how to backup my  
customized and updated Basic MacTeX installation. Would it be  
sufficient to just copy the whole /usr directory to a backup drive?
TIA

Alex