I know some work was done on this not too long ago, so...

...is UNION stable enough to use so long as the independent layers are never
accessed while the union filesystem is mounted?

(I'd like to make a "writable CD-ROM" directory, which would allow me to
update a CD-ROM based FTP/WWW mirror without chewing 600MB of disk space.)

-- 
-- Todd Vierling (tv@pobox.com)