The postgresql.conf file
For the postgresql.conf file, we have to set wal_level to replica or logical. It is important that the WAL level is not set to minimal, because PITR is not possible if wal_level=minimal. We also need to tell PostgreSQL the command that will send the WAL segment to the pgbackrest repository server.
Let’s add these lines at the end of the postgresql.conf file:
#PGBACKREST
archive_mode = on
wal_level = replica #logical if we have some logical replications
archive_command = 'pgbackrest --stanza=pg1 archive-push %p'
With the second line, we say to PostgreSQL that the WAL segments will be archived on the pg1 stanza of the repository server using the pgbackrest command. After restarting PostgreSQL, these new lines will be available. As the root user, let’s perform a restart of the PostgreSQL service:
# systemctl restart postgresql