Hmmm... Some linux systems do not put the $PGDATA directory where we all expect it, Ubuntu comes to mind for that. That said, however, if you ran your "find" as root, and could discover any of the normal subdirectories under the $PGDATA directory. Then I'm at a loss to try to tell you where the database might be. This is just awfully weird. One thought that does come to mind maybe you're missing some NFS or other normally mounted filesystems on this system, but without those subdirectories, PostgreSQL will not run.