There are several methods to do live MySQL database backups. These methods are either storage engine specific (InnoDB hot backup, mysqlhotcopy), or require read locks (mysqldump), or require additional hardware (backup using replication slaves, LVM snapshot). Some of these backup methods can do backups of remote MySQL servers also. So far, there is no backup method that will provide storage engine agnostic, consistent full backups of local and remote servers. Goal of Zmanda Recovery Manager (ZRM) of MySQL is to consolidate all these and future methods of MySQL backup and use the optimal method for the MySQL configuration.
One of exciting developments in MySQL is the development of MySQL Online backup. The functional specification for the MySQL Online Backup APIs are available in MySQL forge and currently, the initial implementation of ARCHIVE storage engine backup and recovery is available in the bitkeeper source tree.
You can read more about MySQL Online Backup and ZRM for MySQL in our blog.