Re: Filespace exhaustion on '/' partition

[David <bouncingcats@gmail.com>]

On 12 May 2014 23:45, Ron Leach <ronleach@tesco.net> wrote:
> On 11/05/2014 22:07, Sven Joachim wrote:
>>
>> A simple "mount --bind / /mnt" makes all those files
>> visible under /mnt, and you can delete them at your leisure.
>>
>
> I mounted the root partition at /mnt/test and used du.
>
> server4:/home/ron# du /mnt/test/mnt -hx --max-depth=1
> 2.7G    /mnt/test/mnt/backupserver
> 0       /mnt/test/mnt/test
> 2.7G    /mnt/test/mnt
> server4:/home/ron#
>
> The 2.7GB is the remnant of a first backup attempt to a new backup server.
> We backup over NFS, to a server mounted at /mnt/backupserver.
>
> During that backup trial, the new backup server was not configured
> correctly, and this machine had not - actually - seen it, though it had
> appeared to do so.  As a result, this machine tried to do a backup to that
> destination, /mnt/backupserver, and had - evidently - filled the root
> partition before complaining about space.
>
> I hadn't understood - then - what had happened, and I corrected (only) the
> missing NFS export and connectivity.  That fix meant that the mountpoint no
> longer 'pointed' to a set of directories on the root partition but - instead
> - to the NFS export (correctly).  A 'proper' backup then succeeded; what I
> hadn't realised, until now, was that the original set of failed-test
> directories was still there, filling the partition and, moreover, now
> invisible.

Whenever I create a directory that is going to be a mountpoint, I immediately
set its immutable attribute to prevent exactly this. Nothing can be
written in an
immutable directory. chattr must be run by root user.

# mkdir mountpoint
# chattr -V +i mountpoint