For same file system df and du command shows different disk usage.

Solution: This could be because of open file deletion, i.e when someone deletes a log file that is being used or open by other processes if we try to delete this file then file name will be deleted buts it’s inode and data will not be deleted.

with the help “lsof” command we can determine the deleted files of /var that are still open :

$ lsof /var | egrep "^COMMAND|deleted"

So to release the space, we can kill the command with its PID using kill command.