If you are running InnoDB, consider running your mysqldump command with the following options:

--single-transaction --quick

This will slow the execution enough that your production site should still stay somewhat performant and not just hijack the server until it completes.

There are associated concerns, of course, but this should get many users through a MySQL dump on a live site.

So, for those of you looking for a complete MySQLDump command example using these switches, try:

Often times people are faced with the cumbersome task of moving an entire database from one environment to another, usually by creating a dump file of the database, moving it across from one database server to another, and re-running the script on the destination. This is irritating in that it requires one to create a file that is immediately disposed of, and to transfer that file one or two times over the wire. It is also prone to error in that it entails many distinct steps that each have their own glitches or mistakes to make. The good news is that the easy, one-step solution exists in a product you just haven't tried yet.