subst performance

Question

Does substing a directory affects the performance creating/reading/updating many small files in the substed volume? (will use svn there) If yes, how serious is the "penalty"?

Answer 1

subst uses native Win32 API DefineDosDevice(), which should not have any noticeable performance penalty.

Answer 2

I use subst'd drives all the time, including with various version controls and builds and have never seen any degradation; I wouldn't worry about it.