This section describes how to initialize the data directory using mysqld, the MySQL server.

The following instructions assume that your current location is the MySQL installation directory, represented here by BASEDIR:

shell> cd BASEDIR

To initialize the data directory, invoke mysqld with the --initialize or --initialize-insecure option, depending on whether you want the server to generate a random initial password for the 'root'@'localhost' account.

On Windows, use one of these commands:

C:\> bin\mysqld --initialize
C:\> bin\mysqld --initialize-insecure

On Unix and Unix-like systems, it is important to make sure that the database directories and files are owned by the mysql login account so that the server has read and write access to them when you run it later. To ensure this, start mysqld from the system root account and include the --user option as shown here:

shell> bin/mysqld --initialize --user=mysql
shell> bin/mysqld --initialize-insecure --user=mysql

Otherwise, execute the program while logged in as mysql, in which case you can omit the --user option from the command.

Regardless of platform, use --initialize for “secure by default” installation (that is, including generation of a random initial root password). In this case, the password is marked as expired and you will need to choose a new one. With the --initialize-insecure option, no root password is generated; it is assumed that you will assign a password to the account in timely fashion before putting the server into production use.

It might be necessary to specify other options such as --basedir or --datadir if mysqld does not identify the correct locations for the installation directory or data directory. For example (enter the command on one line):

shell> bin/mysqld --initialize --user=mysql
         --basedir=/opt/mysql/mysql
         --datadir=/opt/mysql/mysql/data

Alternatively, put the relevant option settings in an option file and pass the name of that file to mysqld. For Unix and Unix-like systems, suppose that the option file name is /opt/mysql/mysql/etc/my.cnf. Put these lines in the file:

[mysqld]
basedir=/opt/mysql/mysql
datadir=/opt/mysql/mysql/data

Then invoke mysqld as follows (enter the command on a single line with the --defaults-file option first):

shell> bin/mysqld --defaults-file=/opt/mysql/mysql/etc/my.cnf
         --initialize --user=mysql

On Windows, suppose that C:\my.ini contains these lines:

[mysqld]
basedir=C:\\Program Files\\MySQL\\MySQL Server 5.7
datadir=D:\\MySQLdata

Then invoke mysqld as follows (the --defaults-file option must be first):

C:\> bin/mysqld --defaults-file=C:\my.ini --initialize

When invoked with the --initialize or --initialize-insecure option, mysqld performs the following initialization sequence.

After you initialize the data directory by starting the server with --initialize or --initialize-insecure, start the server normally (that is, without either of those options) and assign the 'root'@'localhost' account a new password: