From gentoo-user  Thu Mar 08 15:56:18 2012
From: Nikos Chantziaras <realnc () arcor ! de>
Date: Thu, 08 Mar 2012 15:56:18 +0000
To: gentoo-user
Subject: [gentoo-user] Re: Disk usage during emerge
Message-Id: <jjakr7$fcf$1 () dough ! gmane ! org>
X-MARC-Message: https://marc.info/?l=gentoo-user&m=133122236130903

On 08/03/12 16:55, Frank Steinmetzger wrote:
> On Thu, Mar 08, 2012 at 12:50:40PM +0200, Nikos Chantziaras wrote:
>> On 08/03/12 04:57, Frank Steinmetzger wrote:
>>> It came to my attention that during (after) an emerge run, df reports
>>> considerably less space available on my / than before the emerge
>>
>> That's because the old files are not being deleted since they are in
>> use.  When you logout of KDE and restart the whole stack
>> (/etc/init.d/xdm restart) then everything will be back to normal.
>
> By jove, that's definitely it. I knew about this fact from other use cases
> (like deleting a video file which I'm still watching. HA, do that, Windows!),
> but never thought of it regarding emerging. I always assumed for some reason
> that the files were kept in RAM and the physical file itself was no longer
> relevant. Just closing all programs before logging out gave back around 350 M.

I discovered this nifty little tool recently that tells you if any 
deleted files are currently being kept open by running processes: 
"app-admin/checkrestart".  I usually run it after world updates so I can 
tell whether I need a restart or not.