I am designing a dedicated syslog-processing daemon for Linux that needs to be robust and scalable and I\'m debating multithread vs. multiprocess.
The obvious objection
Depends on what programming language you want to use (and which libraries). Personally I would choose multithreading, as I know the problems associated with threads (and how to solve them).
Multiprocessing might help you if you want to run the daemon on multiple machines and distribute the load amongst them, but I don't think that that's a major problem here.