[ybrs]

i read until the backup process and gave up reading through, for cold backups of online databases, you should use percona's extrabackup, its open source and free and works perfectly. http://www.percona.com/doc/percona-xtrabackup/ if you are using mysql a simple googling "hot backup mysql" will lead to that, i guess author didn't even bother to search.

besides, you need to use replication and connect a couple of slaves if you care about being online and backup from one of the slaves - which is a common practice for all databases not for mysql. if you are trying to dump from the master without slaves good luck with any database.

[zorlem]

XtraBackup has its limitations wrt to locking when you've got a mix between InnoDB and MyISAM tables.

The problem with taking a backup from a MySQL slave is that the data is not guaranteed to be identical to the master, thanks to the subtle problems and peculiarities of the MySQL master-slave replication (some of them are described in the OP). For precisely this reason I install an automated job that periodically checksums the tables and sends the results to the DBA role.