1、执行mysqldump命令进行数据备份时, 报错信息如下：

~ % mysqldump -udbuser -p123456 -h127.0.0.1 school student  > school_student.sql 
mysqldump: Got error: 2002: "Can't connect to server on '127.0.0.1' (36)" when trying to connect

2、然后尝试一下命令行连接一下数据库，也是报错

~ % mysql -udbuser -p123456 -h127.0.0.1
ERROR 2002 (HY000): Can't connect to server on '127.0.0.1' (36)

3.查看了一下mysql服务结果没运行，想起来当时使用‘ mysql.server start ’启动数据库，这个不能够跟随系统启动，每次重启MAC需要手动运行。可以使用 brew services start mariadb  随系统启动服务。

~ % mysql.server start
Starting MariaDB
.211111 16:04:44 mysqld_safe Logging to '/usr/local/var/mysql/xiaokang.err'.
211111 16:04:44 mysqld_safe Starting mariadbd daemon with databases from /usr/local/var/mysql
 SUCCESS! 

4、重启成功后再次执行mysqldump进行备份成功