Multiple postmasters for one data directory...

Hi all,

I've got a situation on certain machines where approximately
70 postmasters are running. Each with one database, and one
data directory.

This is fine most of the time, except for a certain time of the month,
when a very large consolidation process has to run on each database.

At this time it is impossible to have all databases started with more shared
memory, and I basically lose the benefits of using a cluster that can make
use of much more memory at a time.

I've managed to make such a database cluster on a separate postmaster,
and re-linked all the database directories to point to the data directories
of all the other postmasters.

Although this workaround seems to be working rather well, I know for one
thing that it could be disastrous to have two postmasters running on the
same data directory at the same time, so I'll ensure that that doesn't happen.

Is what I'm doing VERY bad, and are there more things I'm overlooking?
Can this setup possibly break everything?

Kind Regards
Stefan