/ file system is full, but du does not show that it's full

[Damien Fleuriot]

On 2/28/11 12:24 PM, c0re wrote:
> 2011/1/6 Matthew Seaman <m.seaman at infracaninophile.co.uk>:
>> On 06/01/2011 11:26, c0re wrote:
>>> # df -h
>>> Filesystem     Size    Used   Avail Capacity  Mounted on
>>> /dev/ad0s1a    496M    466M   -9.8M   102%    /
>>>
>>> So it's full.
>>>
>>> But by du it's not appeared to be full
>>>
>>>
>>> # du -hxd 1 /
>>> 2.0K    /.snap
>>> 512B    /dev
>>> 2.0K    /tmp
>>> 2.0K    /usr
>>> 2.0K    /var
>>> 1.9M    /etc
>>> 2.0K    /cdrom
>>> 2.0K    /dist
>>> 1.0M    /bin
>>> 131M    /boot
>>>  10M    /lib
>>> 356K    /libexec
>>> 2.0K    /media
>>>  12K    /mnt
>>> 2.0K    /proc
>>> 7.2M    /rescue
>>> 296K    /root
>>> 4.7M    /sbin
>>> 4.0K    /lost+found
>>> 157M    /
>>>
>>
>> Do you have partitions mounted at /tmp, /usr, /var etc?  Does the output
>> of your du command change if you unmount those partitions?
>> (It might be an idea to boot into a livefs CD or DVD given that du(1)
>> lives in /usr/bin, so a bit tricky to unmount /usr and then run du)
>>
>> My guess is that you've at one time created files beneath what is
>> usually a mount point.  Mounting the partition over them makes those
>> files inaccessible, but they still take up space on the drive.
>>
>>        Cheers,
>>
>>        Matthew
>>
>> --
>> Dr Matthew J Seaman MA, D.Phil.                   7 Priory Courtyard
>>                                                  Flat 3
>> PGP: http://www.infracaninophile.co.uk/pgpkey     Ramsgate
>> JID: matthew at infracaninophile.co.uk               Kent, CT11 9PW
>>
>>
> 
> At last I found time to check it.
> Booted with frenzy life cd, mounted only / partition and saw trash
> /var/spool. Deleted it and it solved problem.
> But later was and idea to mount device of / (/dev/da0s1a) as /mnt/root
> and just delete those files without need of livecd. It works in Linux.
> But in freebsd i got
> 
> # mount /dev/da0s1a /mnt/root/
> mount: /dev/da0s1a : Operation not permitted
> 
> So only single user mode or live cd could solve it.
> 
> Thanks Matthew for an idea!


You're not really trying to umount / on a running system are you ?