MySQL数据库服务器通常指的的是mysqld，而命令行mysql则是mysql客户端程序，这两个概念通常容易混淆。通常启动mysql服务器即是启动mysqld进程，mysqld启动后，可以通过mysql连接到mysql服务器。本文主要描述了mysql服务器的几种启动方式以及如何关闭mysql服务器。
1.直接使用mysqld启动
mysqld 即是mysql服务器，可以调用该命令直接启动mysql服务器.
[root@rhel64a ~]# cat /etc/issue
Red Hat Enterprise Linux Server release 6.4 (Santiago)
1.1查看mysqld启动时的缺省选项
[root@rhel64a ~]# mysqld --print-defaults
mysqld would have been started with the following arguments:
--socket=/tmp/mysql3306.sock --port=3306 --pid-file=/var/lib/mysql/my3306.pid --user=mysql --server-id=3306 --federated [root@rhel64a ~]# ps -ef|grep mysql
root 2963 2840 0 14:10 pts/0 00:00:00 grep mysql
1.2查看mysqld启动配置文件的优先级
[root@rhel64a ~]# mysqld --verbose --help |grep -A 1 "Default options"
Default options are read from the following files in the given order:
/etc/my.cnf /etc/mysql/my.cnf /usr/etc/my.cnf ~/.my.cnf
1.3查看当前的my.cnf配置文件
[root@rhel64a ~]# grep -v ^# /etc/my.cnf|head -n 7
[mysqld]
socket = /tmp/mysql3306.sock
port = 3306
pid-file = /var/lib/mysql/my3306.pid
user = mysql
server-id=3306
federated
1.4查询mysqld进程
[root@rhel64a ~]# ps -ef|grep mysql|grep -v grep
mysql 18240 2641 1 20:25 pts/2 00:00:00 mysqld
[root@rhel64a ~]# mysql -uroot -pxxx -P3306 --protocol=tcp
root@localhost[(none)]> show variables like 'version';
+---------------+--------+ |
Variable_name | Value |
+---------------+--------+ |
version | 5.6.21 |
+---------------+--------+
2.mysql安全启动(mysqld_safe)
[root@rhel64a ~]# mysqladmin -uroot -pxxx shutdown -S /tmp/mysql3306.sock
[root@rhel64a ~]# mysqld_safe --user=mysql &