I am going to trace every actions happened in the services which are managed by the Unity Container as logs in file system. I suppose I could define an interface named IServ
There are many ways to implement the logger. Long time ago I wrote an article about how to set up interceptors:
http://hmadrigal.wordpress.com/2010/12/25/aspect-oriented-programming-and-interceptor-design-pattern-with-unity-2/
For logging you could use Debug.Write, and configure TraceListeners. Or also you could Use Enterprise Library or any third party log library.
Kind regards, Herber