Problem with MySQL when install iRedMail 0.9.2

==== Required information ====
- iRedMail version: 0.9.2
- Store mail accounts in which backend: MySQL
- Web server: Apache
- Linux/BSD distribution name and version: CentOS 6.5, 64bit.
- Related log if you're reporting an issue:
====
I 've got these errors when installing iRedMail.

Error: Package: perl-DBD-MySQL-4.013-3.el6.x86_64 (base)
           Requires: libmysqlclient.so.16()(64bit)
Error: Package: 1:dovecot-2.1.17-0_136.el6.x86_64 (iRedMail)
           Requires: libmysqlclient.so.16(libmysqlclient_16)(64bit)
Error: Package: perl-DBD-MySQL-4.013-3.el6.x86_64 (base)
           Requires: libmysqlclient.so.16(libmysqlclient_16)(64bit)
Error: Package: 3:postfix-2.11.0-0.el6.x86_64 (iRedMail)
           Requires: libmysqlclient.so.16(libmysqlclient_16)(64bit)
Error: Package: 1:dovecot-2.1.17-0_136.el6.x86_64 (iRedMail)
           Requires: libmysqlclient.so.16()(64bit)
Error: mariadb-server conflicts with MySQL-server-5.6.20-1.linux_glibc2.5.x86_64
Error: Package: sogo-2.3.0-1.centos6.x86_64 (SOGo)
           Requires: httpd
Error: Package: 3:postfix-2.11.0-0.el6.x86_64 (iRedMail)
           Requires: libmysqlclient.so.16()(64bit)

I was using MySQL version 5.5.31 when I got these errors. Then I upgraded to MySQL 5.6.20 and meet exactly the same errors. Almost all of the errors related to MySQL.
What should I do now? Please help!