ERROR 2006 (HY000) at line xxx: MySQL server has gone away

这个错误消息是你要导入的.sql文件大小超过MySQL设置的值

ERROR 2006 (HY000) at line xxx: MySQL server has gone away

修改
vi /etc/my.cnf

有两个，都修改吧
max_allowed_packet = 1M
max_allowed_packet = 16M

修改为
max_allowed_packet = 1024M

保存并离开
:wq

重新启动数据库
lnmp mariadb restart

或者重启CentOS系统
sudo reboot