建表时指定另外一个目录，结果出错：
mysql> create table t1 (id int primary key,n varchar(10)) data directory='/home/mysql/data'; ERROR 1030 (HY000): Got error 168 from storage engine
在error log中有这样的提示：
2020-01-16T02:29:45.360317Z 2 [ERROR] InnoDB: Operating system error number 13 in a file operation. 2020-01-16T02:29:45.360400Z 2 [ERROR] InnoDB: The error means mysqld does not have the access rights to the directory.
以为是mysqld的权限不对，改了也没有用：
mysql> system sudo -u mysql touch /home/mysql/data/a mysql> create table t1 (id int primary key,n varchar(10)) data directory='/home/mysql/data'; ERROR 1030 (HY000): Got error 168 from storage engine
到处搜索，发现是apparmor惹得祸，
# aa-status| grep mysql /usr/sbin/mysqld /usr/sbin/mysqld (15007)
修改配置文件把相应的目录加上即可： /etc/apparmor.d/usr.sbin.mysqld
或者disable mysqld的
sudo ln -s /etc/apparmor.d/usr.sbin.mysqld /etc/apparmor.d/disable/ sudo apparmor_parser -R /etc/apparmor.d/usr.sbin.mysqld Skipping profile in /etc/apparmor.d/disable: usr.sbin.mysqld
