======== Required information ====
- iRedMail version (check /etc/iredmail-release):  0.9.2
- Linux/BSD distribution name and version: Centos 6.4
- Store mail accounts in which backend (LDAP/MySQL/PGSQL): MySQL
- Web server (Apache or Nginx):Apache
- Manage mail accounts with iRedAdmin-Pro? Yes
- Related log if you're reporting an issue:
====

Dear Sir,

-rw-------  1 root  utmp      1032140160 Mar 24 16:30 btmp
-rw-------  1 vmail vmail     1329859449 Mar 24 16:30 dovecot.log
-rw-------  1 root  root        2421586967 Mar 24 16:25 maillog
-rw-------  1 root  root        30031863 Mar 24 16:25 messages
-rw-r-----. 1 mysql mysql    1711085 Jun 30  2015 mysqld.log
-rw-------  1 root  root        631133115 Mar 24 16:25 secure
-rw-rw-rw-  1 vmail vmail  127319039 Mar 24 16:25 sieve.log

found that some log file is very large, how can i get it smaller or can i delete it?

Thanks!

Roy Wong