Изменяем папку с базами mysql:

# Create new directory for MySQL data
mkdir /new/dir/for/mysql
# Set ownership of new directory to match existing one
chown —reference=/var/lib/mysql /new/dir/for/mysql

# Set permissions on new directory to match existing one
chmod —reference=/var/lib/mysql /new/dir/for/mysql

# Stop MySQL before copying over files
service mysql stop

# Copy all files in default directory, to new one, retaining perms (-p)
cp -rp /var/lib/mysql/* /new/dir/for/mysql/

Edit the /etc/my.cnf file, and under [mysqld] add this line:
datadir=/new/dir/for/mysql/