Differences between "df -m" and summarized "du -sm *" in FC4

[Paul Howarth]

On Tue, 2006-06-13 at 08:13 +0200, Joachim Backes wrote:
> Hi,
> 
> having an FC4 server and problems with /tmp:
> 
> df -m says, that /tmp 100% full. But if going to /tmp, calling "du -sm *" and summarizing all sizes 
> gives a huge difference against the df command (the sum is about 10% of the df-value).
> 
> Remark: there are no .-files in /tmp so "du -sm *" fits all files in /tmp.
> 
> Can somebody explain this behaviour?

You probably have a process running that has a a large open file in /tmp
that has been deleted. The disk space is not recovered for use by other
processes until the file is closed.

Deleting an open temp file is a fairly common technique - it prevents
other processes getting any access to the file.

Paul.