Instead of using a tar method, try using rysnc.
I have written posts about how to use rsync a running server with minimum downtime.
- http://dba.stackexchange.com/questions/174/how-can-i-move-a-database-from-one-server-to-another/2893#2893How can I move a database from one server to another?
- http://dba.stackexchange.com/questions/6806/mysql-community-edition-can-i-replicate-my-entire-server-with-another-server-in/6813#6813MySQL Community Edition: Can I replicate my entire server with another server in one go?
- http://dba.stackexchange.com/questions/8011/any-better-way-out-of-mysql-innodb-log-in-the-future/8026#8026Any better way out of MySQL InnoDB log "in the future"? (See Option 02)
Just make sure
- Binary Logging is enabled on the Master
- you copy /etc/my.cnf from master to new slave
- change the server-id in the slave's my.cnf