.ecryptfs eats up the disc space

Every time I start the system I got a warning that the system is low on disc space and there are something about 2GB left.
At first I didn't care a lot but after a short consideration I asked myself... why? All I have on my desktop are ~65GB of data + one Virtual Mashine <30GB. I started the disc usage analyser and it showed me the photo You can see below:

  1. It sees my 250GB disc as 330,1 GB
  2. In my Home directory there is an .ecryptfs catalog that doubles the actual data size.

I see such thing for the first time in my life. Can anyone explain me what's going on and how can I resolve the problem?