使用另一个数据目录时，mysql服务器将无法工作

Question

我有一个在 Amazon Linux AMI 上运行的亚马逊 ec2 实例。我正在尝试使用以下配置文件（/etc/my.cnf）将 mysql 的数据目录移动到第二个卷（安装在 /home/ec2-user/data）上，但 mysql 无法启动：

[mysqld]
datadir=/home/ec2-user/data/mysql
socket=/home/ec2-user/data/mysql/mysql.sock
log-bin=/var/log/mysql/mariadb-bin
log-bin-index=/var/log/mysql/mariadb-bin.index
symbolic-links=0

[mysqld_safe]
log-error=/var/log/mysqld.log
pid-file=/var/run/mysqld/mysqld.pid

[client]
port=3306
socket=/home/ec2-user/data/mysql/mysql.sock

我在日志文件中收到以下错误消息：

2017-10-12 14:06:33 20082 [ERROR] Can't open the mysql.plugin table. Please run mysql_upgrade to create it.
2017-10-12 14:06:33 20082 [ERROR] Can't start server : Bind on unix socket: Permission denied
2017-10-12 14:06:33 20082 [ERROR] Do you already have another mysqld server running on socket: /home/ec2-user/data/mysql/mysql.sock ?
2017-10-12 14:06:33 20082 [ERROR] Aborting

当我将配置文件设置回以前的设置（到数据文件夹的备份）时，一切正常：

[mysqld]
datadir=/var/lib/mysql.bak
socket=/var/lib/mysql.bak/mysql.sock

log-bin=/var/log/mysql/mariadb-bin
log-bin-index=/var/log/mysql/mariadb-bin.index
symbolic-links=0

[mysqld_safe]
log-error=/var/log/mysqld.log
pid-file=/var/run/mysqld/mysqld.pid

[client]
port=3306
socket=/var/lib/mysql.bak/mysql.sock

这个问题的原因可能是什么？我已经检查了新数据文件夹的权限，但这并没有改变任何东西。

Answer 1

运行这个命令：

chgrp -R mysql /home/ec2-user/data/mysql
chown -R mysql /home/ec2-user/data/mysql

你可以试试下面的配置文件吗？

[mysqld]
datadir=/home/ec2-user/data/mysql
socket=/var/lib/mysql.bak/mysql.sock

log-bin=/var/log/mysql/mariadb-bin
log-bin-index=/var/log/mysql/mariadb-bin.index
symbolic-links=0

[mysqld_safe]
log-error=/var/log/mysqld.log
pid-file=/var/run/mysqld/mysqld.pid

[client]
port=3306
socket=/var/lib/mysql.bak/mysql.sock