An excerpt from smartd manpage reads:
-l FACILITY, --logfacility=FACILITY
Uses syslog facility FACILITY to log the messages from smartd. Here FACILITY is one of local0, local1, ..., local7, or daemon [default]. If this command-line option is not used, then by default messages from smartd are logged to the facility daemon.
Followed by steps how to accomplish this on a syslog based system.
Apparently, if Arch Linux is up-to-date, it runs
journald in conjunction with
systemd for the same purpose. For the latter, I cannot find a way to configure facilities or whatnot.
How to give
smartd a logfile of it's own in a
Mirrored from Arch Linux forums.