On Sun, Mar 09, 2003 at 06:47:34PM -0600, Peter Seebach wrote:
  | So, I have a small mfs filesystem, union-mounted over a directory.
  | 
  | If I create a file there, and then delete it, the space is not reclaimed.
  | If I unmount the union mount, it frees up, and then if I redo the union
  | mount, all is well... but surely I don't need to do that!
  | 
  | Obvious setting?  Just Don't Do That?

I think it's a "known problem" with read-write union mounts.

The freed space will eventually get reported correctly, if you instead
wait until the vnodes get flushed (?).