Comment # 7 on bug 1187130 from Ruediger Oertel

for comment #5 
267G    /z

so there are files taking up 267 Gigabytes below /z outside of the filesystems
mounted there. The actual files there might even be hidden below the mounts
of the other filesystems there. So if you can, you could try to unmount all
the other filesystems from /z/D /z/F /z/G or /z/WD750 and see what is hiding
there.

>> Is there a way to submit code in a compact form (as on the suse forums)?
not really, you can use files and use "attach file" or just post inline like
you did.