I have encrypted my /home folder using ecryptfs. I've noticed that it uses as 1.5 times the disk space compared to when it was not encrypted. Is this problem caused by the eCryptfs and is there a way to deal with it?
eCryptfs will add a small amount of header data to a file, so if you have many thousands of files this could explain some of the extra space being used.
Also, Linux allows files to be non-contiguous and these can have "holes" in them which don't use any space. However, eCryptfs has to encrypt these holes (they are effectively zero blocks which are encrypted) and so this uses up more blocks than the original file that has holes in it. Perhaps that is the reason for the overhead.