$ sudo service postgresql start
* Starting PostgreSQL 11 database server * Error: /usr/lib/postgresql/11/bin/pg_ctl /usr/lib/postgresql/11/bin/pg_ctl start -D /var/lib/postgresql/11/main -l /var/log/postgresql/postgresql-11-main.log -s -o -c config_file="/etc/postgresql/11/main/postgresql.conf" exited with status 1:
2019-03-24 08:12:57.882 DST [13389] LOG: listening on IPv4 address "127.0.0.1", port 5432
2019-03-24 08:12:57.882 DST [13389] LOG: listening on IPv4 address "127.0.0.1", port 5432
2019-03-24 08:12:57.893 DST [13389] LOG: listening on Unix socket "/var/run/postgresql/.s.PGSQL.5432"
2019-03-24 08:12:57.955 DST [13390] LOG: database system was interrupted; last known up at 2019-03-24 08:05:05 DST
2019-03-24 08:12:57.955 DST [13390] PANIC: could not flush dirty data: Function not implemented
2019-03-24 08:12:57.956 DST [13389] LOG: startup process (PID 13390) was terminated by signal 6: Aborted
2019-03-24 08:12:57.956 DST [13389] LOG: aborting startup due to startup process failure
2019-03-24 08:12:57.962 DST [13389] LOG: database system is shut down
pg_ctl: could not start server
Examine the log output.
* Starting PostgreSQL 11 database server * Error: /usr/lib/postgresql/11/bin/pg_ctl /usr/lib/postgresql/11/bin/pg_ctl start -D /var/lib/postgresql/11/main -l /var/log/postgresql/postgresql-11-main.log -s -o -c config_file="/etc/postgresql/11/main/postgresql.conf" exited with status 1:
2019-03-24 08:12:57.882 DST [13389] LOG: listening on IPv4 address "127.0.0.1", port 5432
2019-03-24 08:12:57.882 DST [13389] LOG: listening on IPv4 address "127.0.0.1", port 5432
2019-03-24 08:12:57.893 DST [13389] LOG: listening on Unix socket "/var/run/postgresql/.s.PGSQL.5432"
2019-03-24 08:12:57.955 DST [13390] LOG: database system was interrupted; last known up at 2019-03-24 08:05:05 DST
2019-03-24 08:12:57.955 DST [13390] PANIC: could not flush dirty data: Function not implemented
2019-03-24 08:12:57.956 DST [13389] LOG: startup process (PID 13390) was terminated by signal 6: Aborted
2019-03-24 08:12:57.956 DST [13389] LOG: aborting startup due to startup process failure
2019-03-24 08:12:57.962 DST [13389] LOG: database system is shut down
pg_ctl: could not start server
Examine the log output.