How to monitor a complete directory tree for changes in Linux?

Question

How can I monitor a whole directory tree for changes in Linux (ext3 file system)?

Currently the directory contains about half a million files

Answer 1

I have a different suggestion, only for changes in the files, and record history changes

use git

cd /folder_to_monitor
git init
git add *
git commit -m "first snapshot"

so after you make the changes

git diff