The MySQL Connector/J provides JDBC support for MySQL. Please use an up to date JDBC4 driver for your version of MySQL. The driver can be found here: https://dev.mysql.com/downloads/connector/j/

Copy the driver file to the lib directory of the Content Server installations. Afterwards, you can configure the database as follows:

sql.store.driver=com.mysql.cj.jdbc.Driver
sql.store.url=jdbc:mysql://localhost:3306/<user>
sql.store.user=<user>
sql.store.password=<password>

Replace <user> and <password> as appropriate. Lower case is recommended. You create a separate database and a separate user for each server as follows:

CREATE SCHEMA <user> CHARACTER SET utf8mb4 COLLATE utf8mb4_bin;
CREATE USER '<user>'@'localhost' IDENTIFIED BY '<password>';
CREATE USER '<user>'@'%' IDENTIFIED BY '<password>';
GRANT ALL PRIVILEGES ON <user>.* TO '<user>'@'%', '<user>'@'localhost';

Again, replace <user> and <password>. If not properly set as indicated above, the Content Server will change the character set and the collation of the database to utf8mb4 and utf8mb4_bin during the first start.

All tables will be set up to use the InnoDB storage engine. By default, the caches for this storage engine are configured very small. Consider increasing the MySQL startup option innodb_buffer_pool_size. Also, increasing innodb_log_file_size will improve write performance, because log files are rotated less often.