LARGE single-system Cyrus installs?

[Rob Mueller]

> 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