If you are doing replication and you are just practicing, the my.cnf you choose is not that important. However, the smaller the config, the better. For example, if you DB Server has 2GB RAM, you should not choose my-innodb-heavy-4G.cnf.

If you started up mysql with a my.cnf, you create the default 10M or 18M ibdata1 and 2 5M InnoDB log files (ib_logfile0, ib_logfile1). The medium cnf has the following InnoDB settings:

[root@******** ~]# cat /usr/share/mysql/my-medium.cnf | grep innodb
#innodb_data_home_dir = /var/lib/mysql
#innodb_data_file_path = ibdata1:10M:autoextend
#innodb_log_group_home_dir = /var/lib/mysql
#innodb_buffer_pool_size = 16M
#innodb_additional_mem_pool_size = 2M
#innodb_log_file_size = 5M
#innodb_log_buffer_size = 8M
#innodb_flush_log_at_trx_commit = 1
#innodb_lock_wait_timeout = 50

Since everything related to InnoDB is commented out, you should OK to choose my-medium.cnf

Simply run this:

cp /usr/share/mysql/my-medium.cnf /etc/my.cnf
service mysql restart

Now, as for MySQL Replication, I have Good News : I already answered a post back on Feb 06, 2012 ( How to setup replication(Master/slave) in MySQL 5.5.20? ) with all the steps you need to automate a Slave's creation.

Here is a couple more of my posts with more advanced replication setups

• May 07, 2012 : Setting Circular Replication in mysql
• Sep 24, 2012 : Setting up MySQL circular replication in existing replication topology?
• Nov 26, 2012 : Replicate MySQL 5.0 Master to 5.5 Slave?

The option character-set-database should not be configured in my.cnf.

Please note what the MySQL Documentation says on character-set-database:

The character set used by the default database. The server sets this variable whenever the default database changes. If there is no default database, the variable has the same value as character_set_server.

Footnote : This option is dynamic, but only the server should set this information. You should not set the value of this variable manually.

Even the Documentation says it is dynamic, it not supposed to be dynamically by any manual intervention against my.cnf. If you look inside the database subfolder, you will find a file called db.opt. EXAMPLE : When you run use dbname in the mysql client, the file /var/lib/mysql/dbname/db.opt is read in order to set character-set-specific database options contained in that file. For this reason, the variable has to be dynamic.

If you cannot access the database from the OS to see db.opt, simply run this command:

SHOW CREATE DATABASE dbname;

on any database and you will see what db.opt contains (or defaults if db.opt is not there)

mysql> show create database mysql;
+----------+------------------------------------------------------------------+
| Database | Create Database                                                  |
+----------+------------------------------------------------------------------+
| mysql    | CREATE DATABASE `mysql` /*!40100 DEFAULT CHARACTER SET latin1 */ |
+----------+------------------------------------------------------------------+
1 row in set (0.00 sec)

mysql>

In light of this, you should try setting character-set-server in my.cnf only (or at least remove character-set-database from my.cnf). Then, run service mysql restart.

Give it a Try !!!

UPDATE #1

I sort of dealt with a question like this before : Why default character_set_server is latin1?

Looking back at my old link, I had an idea: I ran this:

mysql> select version();
+-----------+
| version() |
+-----------+
| 5.6.10    |
+-----------+
1 row in set (0.00 sec)

mysql> select * from information_schema.collations where COLLATION_NAME like '%kor%';
+-----------------+--------------------+----+------------+-------------+---------+
| COLLATION_NAME  | CHARACTER_SET_NAME | ID | IS_DEFAULT | IS_COMPILED | SORTLEN |
+-----------------+--------------------+----+------------+-------------+---------+
| euckr_korean_ci | euckr              | 19 | Yes        | Yes         |       1 |
+-----------------+--------------------+----+------------+-------------+---------+
1 row in set (0.00 sec)

mysql>

You could set a Korean character set if need to.

UPDATE #2

You should leave wait_timeout and interactive_timeout out of the [client] and [mysql] groups.