Server Command Options core. pid  is written to the  /cores  directory. On Solaris, use the  coreadm  command to specify where to write the core file and how to name it. For some systems, to get a core file you must also specify the  --core-file-size  option to mysqld_safe . See Section 4.3.2, “mysqld_safe — MySQL Server Startup Script” . On some systems, such as Solaris, you do not get a core file if you are also using the  --user  option. There might be additional restrictions or limitations. For example, it might be necessary to execute  ulimit -c unlimited  before starting the server. Consult your system documentation. The  innodb_buffer_pool_in_core_file  variable can be used to reduce the size of core files on operating systems that support it. For more information, see Section 15.8.3.7, “Excluding Buffer Pool Pages from Core Files” . • --daemonize ,  -D Command-Line Format --daemonize[={OFF|ON}] Type Boolean Default Value OFF This option causes the server to run as a traditional, forking daemon, permitting it to work with operating systems that use systemd for process control. For more information, see Section 2.5.9, “Managing MySQL Server with systemd” . --daemonize  is mutually exclusive with  --initialize  and  --initialize-insecure . If the server is started using the  --daemonize  option and is not connected to a tty device, a default error logging option of  --log-error=""  is used in the absence of an explicit logging option, to direct error output to the default log file. -D  is a synonym for  --daemonize . •  --datadir= dir_name ,  -h  dir_name Command-Line Format --datadir=dir_name System Variable datadir Scope Global Dynamic No SET_VAR  Hint Applies No Type Directory name The path to the MySQL server data directory. This option sets the  datadir  system variable. See the description of that variable. • --debug[= debug_options ] ,  -# [ debug_options ] Command-Line Format --debug[=debug_options] System Variable debug Scope Global, Session Dynamic Yes SET_VAR  Hint Applies No Type String 736