I'm working as a part-time software developer for EasyUni. Its database is so huge that I cannot install on my laptop's internal HDD. I have to look for a way to install it in my portable HDD.
My solution is to create a second PostgreSQL cluster with data directory residing in my portable HDD. This cluster must not be started up automatically, because the portable HDD is not always attached. So my command to create this second cluster is:
sudo pg_createcluster 9.5 second -d /media/quan/Quan-Backup/Postgres/second --start-conf=manual