by Guillermo Madero S..
Hi Stefanos,
Regarding the duplicate files, it is as Visvanath said, you need to get the hash of all the files in your version 1.9 moodledata folder and then check which, or how many of those files, have the same hash. This will let you then determine the size of all duplicate files.
About temporary files, you also need to check in the 1.9 moodledata folder, not in the new 2 version.