Server Configuration Defaults •Section 5.1.10, “Server Status Variables” 640 For the preceding example, where use of  --validate-config  results in display of an error message, the server exit code is 1. Warning and information messages may also be displayed, depending on the log_error_verbosity  value, but do not produce immediate validation termination or an exit code of 1. For example, this command produces multiple warnings, both of which are displayed. But no error occurs, so the exit code is 0: The server terminates as soon as any error is found. For additional checks to occur, correct the initial problem and run the server with  --validate-config  again. If no errors are found, the server terminates with an exit code of 0. If an error is found, the server displays a diagnostic message and terminates with an exit code of 1. For example: mysqld --validate-config As of MySQL 8.0.16, MySQL Server supports a  --validate-config  option that enables the startup configuration to be checked for problems without running the server in normal operational mode: For additional information about option file format and syntax, see Section 4.2.2.2, “Using Option Files” . For non-Windows platforms, no default option file is created during either the server installation or the data directory initialization process. Create your option file by following the instructions given in Section 4.2.2.2, “Using Option Files” . Without an option file, the server just starts with its default settings— see Section 5.1.2, “Server Configuration Defaults”  on how to check those settings. After completing the installation process, you can edit the default option file at any time to modify the parameters used by the server. For example, to use a parameter setting in the file that is commented with a  #  character at the beginning of the line, remove the  # , and modify the parameter value if necessary. To disable a setting, either add a  #  to the beginning of the line or remove it. On Windows, the  .ini  or  .cnf  option file extension might not be displayed. The MySQL server has many operating parameters, which you can change at server startup using command-line options or configuration files (option files). It is also possible to change many parameters at runtime. For general instructions on setting parameters at startup or runtime, see Section 5.1.7, “Server Command Options” , and Section 5.1.8, “Server System Variables” . On Windows, MySQL Installer interacts with the user and creates a file named  my.ini  in the base installation directory as the default option file. More detailed monitoring information is available from the Performance Schema; see Chapter 27,  MySQL Performance Schema . In addition, the MySQL  sys  schema is a set of objects that provides convenient access to data collected by the Performance Schema; see Chapter 28,  MySQL sys Schema . If you specify an option on the command line for  mysqld  or  mysqld_safe , it remains in effect only for that invocation of the server. To use the option every time the server runs, put it in an option file. See Section 4.2.2.2, “Using Option Files” . 5.1.2 Server Configuration Defaults Note 5.1.3 Server Configuration Validation shell>  mysqld --validate-config --no-such-option 2018-11-05T17:50:12.738919Z 0 [ERROR] [MY-000068] [Server] unknown option ’--no-such-option’. 2018-11-05T17:50:12.738962Z 0 [ERROR] [MY-010119] [Server] Aborting