centos6 - Centos , /dev/root is getting full. Cannot find disk space usage

First of all I am not a sysadmin and so this is all new for me.

Running on :CENTOS 6.4 x86_64 , Cpanel/WHM 11.36.1 (build 6)

Problem : My root disk is getting full but I cannot find the files that are causing this.

#df -h
Filesystem            Size  Used Avail Use% Mounted on
rootfs                 39G   34G  3.0G  92% /
/dev/root              39G   34G  3.0G  92% /
none                   12G  472K   12G   1% /dev
/dev/md3              1.8T  7.2G  1.7T   1% /home
/dev/loop0            4.0G  150M  3.6G   4% /tmp
/dev/loop0            4.0G  150M  3.6G   4% /var/tmp

/dev/root              39G   34G  3.0G  92% /var/named/chroot/etc/named
/dev/root              39G   34G  3.0G  92% /var/named/chroot/usr/lib64/bind



du -sh /*

7.4M    /bin
8.6M    /boot
4.0K    /cgroup

472K    /dev
26M     /etc
7.0G    /home
21M     /lib
25M     /lib64
16K     /lost+found
4.0K    /media
4.0K    /mnt
39M     /opt
du: cannot access `/proc/22413/task/22413/ns/net': No such file or directory

du: cannot access `/proc/22413/task/22413/ns/uts': No such file or directory
du: cannot access `/proc/22413/task/22413/ns/ipc': No such file or directory
du: cannot access `/proc/22413/ns/net': No such file or directory
du: cannot access `/proc/22413/ns/uts': No such file or directory
du: cannot access `/proc/22413/ns/ipc': No such file or directory
du: cannot access `/proc/22957/task/22957/fd/4': No such file or directory
du: cannot access `/proc/22957/task/22957/fdinfo/4': No such file or directory
du: cannot access `/proc/22957/fd/4': No such file or directory
du: cannot access `/proc/22957/fdinfo/4': No such file or directory
0       /proc

2.4M    /root
20M     /sbin
0       /scripts
4.0K    /selinux
4.0K    /srv
0       /sys
15M     /tmp
8.0G    /usr
1.3G    /var

How the hell does that make 34GB , since home in on a different partition.
Help much appreciated.