I wanted to move my /var/lib/mysql directory to /data/mysql (a new partition). So I copied copied them and made the appropriate change in /etc/my.cnf. On restarting mysql with /etc/init.d/mysql start, I got a failure. 

On looking in the /var/log/messages file, I found:

Nov 23 17:48:46 carpenomen kernel: [ 2714.258037] audit(1227462526.718:13): type=1503 operation="inode_create" requested_mask="w::" denied_mask="w::" name="/data/mysql/carpenomen.lower-test" pid=19659 profile="/usr/sbin/mysqld" namespace="default"
Nov 23 17:48:46 carpenomen kernel: [ 2714.310572] audit(1227462526.770:14): type=1503 operation="inode_permission" requested_mask="rw::" denied_mask="rw::" name="/data/mysql/ibdata1" pid=19659 profile="/usr/sbin/mysqld" namespace="default"