Two Mysql Instances

1. install mysql
2. copy the mysql data directory to say mysql1

So you have /var/db/mysql and /var/db/mysql1

1. Open the first mysql /var/db/mysql/my.cnf

   Change

    port = <The port you want the first mysql to listen to>
    bind-address = <The ip you want the first mysql to bind to>

1. start the first mysql server

2. Open the second mysql /var/db/mysql1/my.cnf

   Change

   port = <The port you want the second mysql to listen to>
   bind-address = <The ip you want the second mysql to bind to>
   

3. Write the startup command for the second mysql server

   /usr/local/bin/mysqld_safe --bind-address=<The ip address you want to bind
   the second mysql server to> --user=mysql --socket=/tmp/mysql1.sock
   --datadir=/var/db/mysql1 --pid-file=/var/run/mysql1.pid &
   

This works great for n number of mysql servers. Tested and working on one of my live servers.

further reference