[Discuss] strange behaviour

[me at mattgillen.net (Matthew Gillen)]

On 07/01/2011 11:23 AM, dan moylan wrote:
> 
> last night, running ubuntu 11.04 on acer d255e, i got a
> pop-up window advising me that i was running out of disk
> space.  sure enough, df told me that i was at 98% with less
> that 1GB out of 40 available on /home.  so i went to /home,
> but du -s showed only 21GB in use. ???  i shut down and went
> to bed puzzled.
> 
> today, i fired up and df shows 21GB in use.

Yep, I got some help on this list for that very issue.  The old archives
would have been here:
 http://lists.blu.org/pipermail/discuss/2009-November/034551.html

But the long and short of it is next time, try this:
 lsof | grep deleted

Deleted files (or tmp files) that still have some process holding a file
descriptor take up space (but won't show up in a 'du' analysis).  So
likely you had some runaway process that was logging a boatload of stuff
to a file that got deleted after the process started writing to it.

Your shutdown killed the process, and thus freed the last fd referencing
the file, so the space was finally reclaimed.

Matt