I've been having some serious problems with both rsync and unison hanging. I run both in daemon mode, with a dial-up client to an ISDN server. The setup works fine from one machine, and would consistently hang on another. I changed the hardware on the problem client completely (from a p5/166 to a celeron 333, swapped modems) and still the problem persisted. Basically, at some point, rsync or unison would simply quit sending data. The problem turned out to be the hardware - both motherboards on the problem clinet would lose serial interrupts when the IDE drive was under severe load. I have now replaced the cheap mobo the celeron lived on with a Tyan Tiger 100 mobo and last night the sync finally ran for the first time in a week - for 12 hours straight. Anyway, lesson learned - I wasted an enormous amount of time testing the various sync packages, my VPN software, phone lines, ISDN lines, ISDN modems, etc. etc... - when the problem was cheap mobos.... My recommendation if you're seeing freezes on a serial line and are using IDE drives - check if the mobo is dropping interrupts. --Yan
