i know this may not have a right answer but if we're planning a site which has about 20000 users. will you recommend just run whole users in one single server or at least 2-server?
the second question is about partition size, according to the mail quota planning, it needs almost 2TB available size. in terms of performance, will you recommend to use multiple message-store such as 1TB first, and then 1TB next....etc. or just create one 2-TB partition?
(we will run the community edition : ZCS 6.0.x)