Hi there and welcome!!
If you could PUTTY into your server and capture the output of this command when run from the /etc folder:
ls -RlhaS
This will give you a listing of all the files in this folder structure sorted by size. Hopefully something leaps off the screen at you then.
If you want, you could also capture the output and attach here as a file for people to peruse and maybe spot something for you as well!
Kind regards.