While taking backup of mysql if someone wants to add something to database will mysql allows that or not.
depends on how you want to do it. Some people take the server down, other use something like "mysqlhotcopy" or whatever.
Here's some docs: http://www.mysql.com/doc/en/Backing_up.html http://www.mysql.com/doc/en/Backup.html http://www.mysql.com/doc/en/mysqldump.html
