> However observationally we find that under high email usage that > above 10K users on a Cyrus instance things get really bad. Like last > week we had a T2000 at about 10,500 users and loads of 5+ and it > was bogging down. We moved 1K users off bringing it down to > 9,500 and loads dropped to around 1.0 and everything is fine. With 10k users, how much disk space and how many peak simultaneous imap connections does 10k users represent on your system? It's just that I imagine the number of actual users on a system isn't the pure bottleneck per-se, it's really some relationship between number-of-users (more users means more email deliveries) and number-of-users*percent-that-are-connected (more users that connect more often means more imapd processes). Rob ---- Cyrus Home Page: http://cyrusimap.web.cmu.edu/ Cyrus Wiki/FAQ: http://cyrusimap.web.cmu.edu/twiki List Archives/Info: http://asg.web.cmu.edu/cyrus/mailing-list.html