Where can I find documentation on my.cnf directives?

Question

I'm skimming through how to set up a basic master/slave replication in mysql. http://crazytoon.com/2008/01/29/mysql-how-do-you-set-up-masterslave-replication-in-mysql-centos-rhel-fedora/

However when I did a google search on some of the directives like 'relay-log' or 'server-id' under the [mysqld] option I could not find a page that explains each directive.

Is there a place I can go to that annotates all the directives that can be used in my.cnf and what they do?

Answer 1

If you look at the MySQL documentation, you will notice the following line:

Any long option that may be given on the command line when running a MySQL program can be given in an option file as well. To get the list of available options for a program, run it with the --help option.

Further details clarify the above statement:

The syntax for specifying options in an option file is similar to command-line syntax.. However, in an option file, you omit the leading two dashes from the option name and you specify only one option per line. For example, --quick and --host=localhost on the command line should be specified as quick and host=localhost on separate lines in an option file. To specify an option of the form --loose-opt_name in an option file, write it as loose-opt_name.

The list of options, therefore, is provided in the MAN page for the appropriate program (e.g. the 'mysql' section or the mysqld section, etc. or by running mysql --help or mysqld --verbose --help) (Also see the MySQL Docs for replication specific options: Slave and Master)

For instance, for your two examples:

server-id

      The server ID. This value is set by the --server-id option. It is
      used for replication to enable master and slave servers to identify
      themselves uniquely. This variable was added in MySQL 3.23.26.

relay-log=file_name

       The basename for the relay log. The default basename is host_name-relay-bin.
       The server writes the file in the data directory unless the basename is given
       with a leading absolute path name to specify a different directory. The server
       creates relay log files in sequence by adding a numeric suffix to the basename.