We have recently been through that exact upgrade, also on CentOS. We experienced no trouble at all with any of our databases, all using the InnoDB engine. I have enclosed our internal upgrade how-to, this may save you some time and show you which path we took.
This guide assumes you are running the AMD64 versjon og CentOS 6.
Create a yum repo file for MariaDB and name it /etc/yum.repos.d/MariaDB.repo
[mariadb] name = MariaDB baseurl = http://yum.mariadb.org/10.0/centos6-amd64 gpgkey=https://yum.mariadb.org/RPM-GPG-KEY-MariaDB gpgcheck=1 // The signing key value is 0x1BB943DB.
Uninstall current MariaDB server and client. If yum was used to install them, use:
yum remove mysql MySQL-server MySQL-shared MySQL-shared-compat
This should uninstall all packages depending on MariaDB/MySQL, and consequently requires you to reinstall php-mysql as described below. Any other packages depending on MySQL will also have to be reinstalled, so keep an eye out for this.
Install MariaDB
yum install MariaDB-server MariaDB-client
Reinstall PHPs MySQL lib
yum install php-mysql
Start MariaDB, update data files and restart Apache
service mysql start
mysql_upgrade
service httpd restart
Consider rebooting to test that all works as desired.