the result of "df -h" shows below:
/dev/sda1 5.6G 3.2G 2.2G 60% / udev 992M 4.0K 992M 1% /dev tmpfs 401M 752K 401M 1% /run none 5.0M 0 5.0M 0% /run/lock none 1002M 0 1002M 0% /run/shm
the result of "du -hs /" shows below:
Why is that?
df and du measure two different things....
du reports the space used by files and folders--even this is more than the file size. A few quick experiments on my system show that 4K is a minimum file size in terms of disk space.
df reports the space used by the file system. This includes the overhead for journals and inode tables and such.