Yes, that certainly ought to work.
If what you're meaning is that you make a replica that sits in
/opt/VERSION8, and then, once the upgrade is complete, rename that to
/opt/MYDATABASE which was where your version 7.4 DB used to be.
We have copied databases from one server to another by copying the
files; making it work was as easy as making sure we ran "pg_ctl -D
$RIGHT_DIRECTORY start" :-).
--
let name="cbbrowne" and tld="cbbrowne.com" in name ^ "@" ^ tld;;
http://cbbrowne.com/info/lisp.html
"I don't know why, but first C programs tend to look a lot worse than
first programs in any other language (maybe except for FORTRAN, but
then I suspect all FORTRAN programs look like `firsts')" -- Olaf Kirch