Duff-Man says....Heb1228 is right - this gets asked a lot....so my friendly 🙂 suggestion is - try using the search feature of the forum. A simple search using the term "defrag" would show you just how many times this does get asked.
Finding your answer through the search function has 2 good effects - it prevents the forums from getting cluttered up with duplicate threads, and you get your answer faster as you do not have to wait for someone to respond......oh yeah!