How to move PostgreSQL DBs

Downtime: however long rsync takes

Step 1.

$ service postgresql stop
$ service postgresql status # make sure that it's really stopped
$ rsync -a --info=progress2 /var/lib/postgresql/ /new_location/postgresql/ # take note of trailing slashes

Step 2.

1. Open /etc/postgresql/10/main/postgresql.conf
2. Look for data_directory setting
3. Change from /var/lib/postgresql/... to /new_location/postgresql/...

Step 3.

$ service postgresql start