So I was in the middle of refreshing my vmbuiler sources when I got an out-of-disk error in the middle of the bzr pull. Fine, so I fired up Filelight, excluded /media and checked to see how much was being used... 5GBs. On a 19GB partition. Feeling this to be a bit odd I figured I'd rather extend the partition another gigabyte. I fire up the Ubuntu partiton, load gparted, and.... it reports the Debian partition as being 5GBs used. Odd. So I extend the partition back a gig, which takes a great deal of time. That's done, so I remount the new debian, fixup grub, restart, and get a kernel panic.
It is at this point that I remember that I had hibernated Debian instaed of shutting it down, and then I moved the filesystem out from under it. So I reboot again, it works. First thing I do after login is check "df"... and the drive reports 5GBs used.
I'm not a master at kernel internals but I have at least part of an inkling that the missing 14 gigabytes of space had something to do with hibernating and restoring the machine multiple times.
In other news it looks like there is a branch vmbuilder-gui, which I'll have to look into sometime.
