I've noticed that syslogd falls over a lot on my Mac OS X 10.4 Server ("mostly dead", as opposed to all dead -- some logs still accumulate). I normally notice when I need to check the mail logs because of a problem. The discovery that my mail logs are empty greatly aggravates the original problem (and me!).

syslogd is supposed to reload on "killall -HUP syslogd", but that never works for me. The functional solution is "sudo launchctl stop com.apple.syslogd; sudo launchctl start com.apple.syslogd", which gets the logs logging properly again.