How to create a new instance of PostgresSQL on OS-X 10.8 Server
"all others databases and roles created by my own are lost!"


I can't speak to the best practices for creating a new database, but as part of the Mountain Lion Server upgrade all of the "old" Postgres data should have been backed up to a subdirectory under /Library(/Server?)  Unfortunately as soon as I discovered this I moved-and-renamed the directory for safekeeping so I don't have the exact name!

I have a completely separate install of Postgres that I built myself for webapp purposes, but I certainly wouldn't call what my approach a "best practice". Largely what I did was build a "stock" install using a very similar set of configure parameters as Apple did (discovered by running pg_config) but with a different install location and default port setting. Following that I coptied-and-tweaked /Applications/Server.app/Contents/ServerRoot/System/Library/LaunchDaemons/org.postgresql.postgres.plist and that's worked fine for me so far.