OK, not sure if the instructions here are out-dated or anything.
I have a forum that I mucked up the O/S. So, like a good cloud citizen, I spun up a brand new shiny Ubuntu 17.10 VM and followed the above instructions.
First thing that I found out immediately is that I need to be root to rsync the files. The rsync command came back with a pile of permission denied errors without copying anything.
Turns out that /var/discourse is owned by root (thanks to sudo mkdir -p /var/discourse in the instructions). Nothing a little hack won’t fix, so I did sudo chown 777 /var/discourse and did the rsync again.
This time it copied most of the files (but unfortunately all owned by me instead of root… probably needs a chown somewhere down the line).
The PostgreSQL files won’t copy and came back as permission denied. I checked the directories on the remote machine and lo and behold those directories are accessible only by root, not by mere mortals.
Using sudo on the rsync didn’t work either because it then asked for the password for root on the remote machine, which is also Ubuntu and thus root doesn’t have a password.
At the end, I gave up and installed a brand new Discourse installation then restored from backup.
I think the above instructions need serious rework especially wrt file ownerships and permissions.