AWS instance not showing the correct free space

I use AWS and I got an EC2 instance. When I run the command
du -h --max-depth=1

I get:

and When I run the command df -h

I get:

It look I use only 1GB but it show that I am using 7.1GB. So I run the command lsof +L1 to locate some deleted file that process are still using and I found 2 of them:

Then I try to kill those processes,also try to use /proc/PID/fd (> FD) and I try to restart my EC2 instance but none of those thing help me to free the space. The process are always return and I can’t figure up why.

Answer

du begins in the current directory. Change the directory:

cd /

Then try your du command again.

Alternatively, tell du to start with the root directory:

du -h --max-depth=1 /

Reference and further reading: http://www.linfo.org/du.html