I recently experimented with installing multiple MySQL instances on one
machine - here's what my experiences were:
In Windows, it was very easy, you would only have to make a 2nd
installation, using a different location and a different port. Then you'd
have to install a second service (I suppose, you'd like to run it as
service/deamon) and redirect the second installation to the different
service (MySQL Administrator is a great tool for this). That's all you
should have to do (except setting the MySQL privileges of course).
With Linux, there's a little more to do - again you would have to install
the second server on a different location. You need to run the
mysql_install_db script (if you install it using the tar.gz file) and
install the mysql.server in the /etc/init.d directory (of course, use
another name as the existing start up file for the other server). You will
probably have to make some changes in it - to set the data directory, the
base directory, the different port and maybe other things. You should also
make the same settings in the my.cnf file, which should be located in the
data directory of each MySQL installation.
You also shouldn't forget to set the permissions right and it's good
practice to start the server with a separate user (mostly mysql) that only
has the required Linux privileges to do what's really necessary.
As Bill already said, you should be careful that both servers don't share
any resources - the minimum is to set different data locations and different
ports, but you should keep everything separated: the configuration files,
the InnoDB tablespaces, the log file locations a.s.o.
The best practice to transfer the data will be mysqldump - I don't think,
there is a more efficient (and secure) way to backup and restore your data.
However, you should also read this:
http://dev.mysql.com/doc/refman/5.0/...e-servers.html
Wish you good luck ;-)!
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