Output from VM experiencing rebuild issue:
drwxr-xr-x 2 101 104 4.0K Jun 15 2020 postgres_backup
drwx------ 19 101 104 4.0K May 3 2022 postgres_data
drwxrwsr-x 5 101 104 4.0K May 3 2022 postgres_run
drwxr-xr-x 2 103 106 4.0K May 3 2022 redis_data
Just a note, something slightly different in my case.
The rebuild got stuck on The database system is ready to accept connections as others have seen. Had to reboot the VM and run ./launcher start app to start the Forums. However, when Discourse was back up, the Discourse version remained at the previous version 3.3.0.beta4-dev.
Am unable to perform the Ubuntu upgrade today, but keep everyone posted when I can and if the rebuild is then successful.
I did bump our dev instance to Ubuntu 20.6 today and the rebuild / upgrade was successful to Discourse 3.4.0.beta2-dev. However, this was the host that also rebuilt without problems on Ubuntu 18.4 yesterday.