dovecot - Dec 2011 - Tuning Login processes for High-performance Mode

Hi,

I'm working for tuning a busy cluster of dovecot servers. Heach server 
as 4 core, 8GB of RAM and provide POP3 and IMAP access to mailbox. OS is 
Debian 6.0 and dovecot version is 1.2.15.

I am unsure how to set "login_max_processes_count" and 
"login_max_connections" for reach the best situation when 
login_process_per_connection is set to no.

I don't know what value to set login_max_processes_count.

For example is better the first or the second configuration?

login_process_per_connection=no
login_processes_count=4
login_max_processes_count=8
login_max_connections=512
login_process_size=128

login_process_per_connection=no
login_processes_count=4
login_max_processes_count=16
login_max_connections=256
login_process_size=128

Which is a suggested ratio from login_max_processes_count and 
login_max_connections ?

Other values are correct?

Thanks
-- 
Alessio Cecchi is:
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On 16.12.2011, at 14.06, Alessio Cecchi wrote:
> I'm working for tuning a busy cluster of dovecot servers. Heach server
as 4 core, 8GB of RAM and provide POP3 and IMAP access to mailbox. OS is Debian
6.0 and dovecot version is 1.2.15.
> 
> I am unsure how to set "login_max_processes_count" and
"login_max_connections" for reach the best situation when
login_process_per_connection is set to no.
They need to be high enough to handle all the concurrent login / SSL
connections.
> I don't know what value to set login_max_processes_count.
This doesn't matter so much as login_processes_count. In normal operation
the login_processes_count should be around 1-2x of the number of CPU cores.
There's no reason to create more processes, so the login_max_process_count
might as well be the same as login_processes_count. The login_max_connections
then just needs to be high enough.