If you need to specify startup options when you run the server, you can indicate them on the command line or place them in an option file. For options that are used every time the server starts, you may find it most convenient to use an option file to specify your MySQL configuration. This is particularly true under the following circumstances:
The installation or data directory locations are different from the default locations (
C:\Program Files\MySQL\MySQL Server 5.1and
C:\Program Files\MySQL\MySQL Server 5.1\data).
You need to tune the server settings, such as memory, cache, or InnoDB configuration information.
When the MySQL server starts on Windows, it looks for option
files in several locations, such as the Windows directory,
C:\, and the MySQL installation directory
(for the full list of locations, see
Using Option Files). The Windows directory typically
is named something like
C:\WINDOWS. You can
determine its exact location from the value of the
WINDIR environment variable using the
MySQL looks for options in each location first in the
my.ini file, and then in the
my.cnf file. However, to avoid confusion,
it is best if you use only one file. If your PC uses a boot
C: is not the boot drive, your
only option is to use the
Whichever option file you use, it must be a plain text file.
You can also make use of the example option files included with your MySQL distribution; see Server Configuration Defaults.
An option file can be created and modified with any text editor,
such as Notepad. For example, if MySQL is installed in
E:\mysql and the data directory is in
E:\mydata\data, you can create an option
file containing a
[mysqld] section to specify
values for the
[mysqld] # set basedir to your installation path basedir=E:/mysql # set datadir to the location of your data directory datadir=E:/mydata/data
Microsoft Windows path names are specified in option files using (forward) slashes rather than backslashes. If you do use backslashes, double them:
[mysqld] # set basedir to your installation path basedir=E:\\mysql # set datadir to the location of your data directory datadir=E:\\mydata\\data
The rules for use of backslash in option file values are given in Using Option Files.
In MySQL 5.1.23 and earlier, the MySQL installer places the data
directory directly under the directory where you install MySQL.
On MySQL 5.1.24 and later, the data directory is located within
AppData directory for the user running
If you would like to use a data directory in a different
location, you should copy the entire contents of the
data directory to the new location. For
example, if you want to use
the data directory instead, you must do two things:
Move the entire
datadirectory and all of its contents from the default location (for example
C:\Program Files\MySQL\MySQL Server 5.1\data) to
--datadiroption to specify the new data directory location each time you start the server.