In case that, for some reasons (such as a prolonged power failure) the archive
machine has to automatically reboot (that is without anybody to shut down
the archive pipeline properly), the start_archive command will
still be invoked at the end of the boot process. Of course, the daemons
that were running at the time of shutdown won't be restarted because
a manual check is required. When this is done, see 6.1.2 to restart
them.