System disk full, can't see where it goes

I have the problem that I cannot login into the webgui and found that my system disk is full. I can't however find out where the space is gone to.
Any help is appreciated!

root@openmediavault:/# df -h
Filesystem      Size  Used Avail Use% Mounted on
rootfs           71G   70G     0 100% /
devtmpfs        1.9G     0  1.9G   0% /dev
tmpfs           385M  4.5M  380M   2% /run
/dev/sda1        71G   70G     0 100% /
tmpfs           5.0M     0  5.0M   0% /run/lock
tmpfs           1.4G  8.0K  1.4G   1% /run/shm
tmpfs           1.9G   40K  1.9G   1% /tmp
/dev/sdb1       2.7T  464G  2.3T  17% /media/743eaf00-aa1b-4cab-a363-6ceeb2a5b88f

root@openmediavault:/# du -hsk * | sort -nr
du: cannot access `proc/31641/task/31641/fd/4': No such file or directory
du: cannot access `proc/31641/task/31641/fdinfo/4': No such file or directory
du: cannot access `proc/31641/fd/4': No such file or directory
du: cannot access `proc/31641/fdinfo/4': No such file or directory
554594792       media
1791768 usr
1489076 var
516688  home
324764  lib
311420  opt
45404   boot
13600   root
11036   sbin
8376    etc
7320    bin
4560    run
32      tmp
16      srv
16      lost+found
4       selinux
4       mnt
4       lib64
4       export
0       vmlinuz.old
0       vmlinuz
0       sys
0       proc
0       initrd.img.old
0       initrd.img
0       dev
0       5.2
0       5.1

Anybody an idea?

Same result

Zitat

root@openmediavault:/# du -hs * | sort -nr
du: cannot access `proc/32487/task/32487/fd/4': No such file or directory
du: cannot access `proc/32487/task/32487/fdinfo/4': No such file or directory
du: cannot access `proc/32487/fd/4': No such file or directory
du: cannot access `proc/32487/fdinfo/4': No such file or directory
533G media
505M home
318M lib
305M opt
45M boot
32K tmp
16K srv
16K lost+found
14M root
11M sbin
9.7M run
8.2M etc
7.2M bin
4.0K selinux
4.0K mnt
4.0K lib64
4.0K export
1.8G usr
1.5G var
0 vmlinuz.old
0 vmlinuz
0 sys
0 proc
0 initrd.img.old
0 initrd.img
0 dev
0 5.2
0 5.1

Alles anzeigen

Zitat

root@openmediavault:/usr# du -hs * | sort -nr
955M lib
856K local
530M share
131M include
101M bin
34M sbin
4.0K src
4.0K games

Alles anzeigen

Zitat

root@openmediavault:/var# du -hs * | sort -nr
772K backups
658M subsonic
554M cache
131M lib
120K spool
92M log
11M opt
5.1M www
4.0K tmp
4.0K mail
4.0K local
4.0K agentx
0 run
0 lock

Alles anzeigen

Zitat

339M mcmyadmin
167M deluge-daemon
44K subsonic
16K extplorer

Nothing really substantial if you ask me..
I previously had problems with full disks due to the remoteshare plugin (webdav/ davfs2 cache) but the /var/cache/davfs2 folder is empty this time.
I installed the backup plugin for the system disk but had no time to configure it, could that be it? I don't know where I should be able to find those files if they exist?

@ryecoaaron Thanks! It was indeed data written to an unmounted disk, I could unmount it and delete the files that were still there, but weren't supposed to be there (since the data was simply a copy of already existing data)