

Dovecot performance tuning
==========================




Disk I/O optimization
=====================


Usually heavily loaded IMAP and POP3 servers don't use much CPU, but they use all the disk I/O they can get. So reducing disk I/O is probably the most useful optimization you can do. 

 * See >>MailLocation/LocalDisk<< for generic disk I/O optimizations. 
 * See >>MailLocation/Mbox<< for mbox-specific optimizations. 
 * See >>MailLocation/Maildir<< for Maildir-specific optimizations. 


CPU usage optimization
======================



 * See >>LoginProcess<< for optimizing CPU usage caused by logins 
 * See 'auth_cache_size' setting for caching passdb and userdb lookups 


Memory usage optimization
=========================


There aren't many settings which affect Dovecot's memory usage. About the only such settings are 'auth_cache_size' and >>LoginProcess<< settings. In general Dovecot uses as much memory as it needs, which is usually quite little. 
Note that these settings do not directly affect the memory usage: 

 * 'login/mail/auth_process_size': These are simply safe guards against potential memory leaks. If the process's virtual size reaches the limit, the process is killed by the kernel. 
 * 'login_max_processes_count', 'max_mail_processes' and 'auth_worker_max_count': These are mostly to avoid DoS attacks using up all your memory. 

(This file was created from the wiki on 2007-12-11 04:42)
