Can you imagine an hourly backup on a Master MySQL server with a lot of data?

The whole application “freezes” up.

On the other hand, when you use this, you need to remember that since it doesn’t lock the table, it’s possible for new data to be inserted (which can also be a bad thing).

For example, if you insert two lines per application “event”, you may only get one of the lines in the backup. The same goes for multiple tables with JOINs.

If you insert multiple rows into multiple tables, there’s a chance you’ll get partial data.

The safest way is to either lock all tables of deny access to the db server.

To prevent downtime, it’s recommended to setup slave servers, you can do pretty much anything you want on them (stop slave; mysqldump; start slave;).

Good luck!