$ systemctl status postgresql-9.4 | head -n 2
postgresql-9.4.service - PostgreSQL 9.4 database server
   Loaded: loaded (/usr/lib/systemd/system/postgresql-9.4.service; enabled)

$ grep ^ExecStart= /usr/lib/systemd/system/postgresql-9.4.service
ExecStart=/usr/pgsql-9.4/bin/pg_ctl start -D ${PGDATA} -s -w -t 600

$ grep ^log_min_messages /var/lib/pgsql/9.4/data/postgresql.conf
log_min_messages = debug5