RE: pg_upgrade -c cannot be run if old cluster is running

[Alain Bourgeois]

When the cluster was created, we did initdb  /var/lib/pgsql10/data, the 
storagebox was not available.
Then storagebox was delivered, we copied data folder to storagebox in 
/mnt/pgdata/pgdir and changed postgresql.conf. We didn't delete existing 
datafiles from /var/lib/pgsql10/data (db was empty).