I have a git-annex repository located at ~/annex which has been set up using git-annex assistant.

This repository is configured as "client".

My other repository is a huge USB drive configured as "full archive".

Now everything seems to work fine except there is one thing I don't understand:

alip@client:~/annex> git-annex whereis ./archive/kus.png
whereis archive/kus.png (1 copy) 
    e79a4cf6-4c48-4833-93de-98ba6eb625d6 -- deniz
ok

Fine, there is only one copy according to git-annex but the file is still present in this client repository:

alip@client:> du -hs ~/annex/archive
20G /home/alip/annex/archive/

How do I free this space? Am I supposed to call git-annex drop manually?

git-annex version: 3.20130124