klimenko.n@theitidea.ru writes:

how to calculate the expected number of imap processes?

Set your mail_max_userip_connections to a large value (~20) and run "doveadm who" periodically to look at your user's actual connection counts.

how many imap processes must be used for each user? i have 6-7 connection for each one user is it normal behavior?

It's typical. Some popular mail readers open about 5, some more, some less. I set my mail_max_userip_connections at 12 even though there are some users who regularly bump up against this. They don't seem to notice -- dovecot probably bumps off the least recently used connection and their mail reader reconnects if it needs to open that mailbox again.

Joseph Tam jtam.home@gmail.com