[Dovecot] Too many imap connections in state "idling"

[3.listas@adminlinux.com.br]

Hi,

I have a "Ubuntu12.04 + dovecot-2.0.19" configuration in my server. My 
mailbox server is shared by ~ 10k domains. It works fine with ~50k 
accounts.

On average, my server has about 6K simultaneous imap connections during 
office hours. But I've noticed that this server has an average of 
approximately 4k connections in state "idling".

On other Dovecot servers the average connections in state "idling" is 
only 10%.

My doveconf -n:
http://thiagoh.prv.digirati.com.br/doveconf-n.txt

Can someone help me?

Thanks
-- 
Thiago Henrique
adminlinux.com.br