Strange case of deleting lots of files and "df" not recognizing it....(unless I umount/mount) the disk...

[Dave Chinner]

On Sun, Jun 24, 2012 at 10:58:12PM -0700, Linda Walsh wrote:
> This isn't that big of a deal, as I'm not close to the limit,
> but I pruned a backup disk that was at 87% full (1.5T free), down
> by 3.8T.  Indeed, doing a 'du' of the disk shows space is ~6-7T (/11T)
> but df still shows 9.5T usage.
> 
> I've done sync a few times, but the files were deleted almost a half an hour
> ago.
> 
> So when does it actually synchronize w/o me forcing it?  (I.e. umount/mount)?

As ben said, the last reference has to go away before the space is
freed. lsof is your friend.

Cheers,

Dave.
-- 
Dave Chinner
david at fromorbit.com