更改数据目录后重新启动mysql

Question

我尝试按照以下说明更改 mysql 的数据目录这里。但现在我无法让mysql重新启动。链接文章中的最后一步是

    $ sudo systemctl start mysql

但我收到以下错误

    Job for mysql.service failed because the control process exited with error code. 
    See "systemctl status mysql.service" and "journalctl -xe" for details.

journalctl -xe 中的信息如下：

    Sep 10 16:03:06 systemd[1]: mysql.service: Service hold-off time over, scheduling restart.
    Sep 10 16:03:06 systemd[1]: mysql.service: Scheduled restart job, restart counter is at 5.
    -- Subject: Automatic restarting of a unit has been scheduled
    -- Defined-By: systemd
    -- 
    -- Automatic restarting of the unit mysql.service has been scheduled, as the result for
    -- the configured Restart= setting for the unit.
    Sep 10 16:03:06 systemd[1]: Stopped MySQL Community Server.
    -- Subject: Unit mysql.service has finished shutting down
    -- Defined-By: systemd
    -- 
    -- Unit mysql.service has finished shutting down.
    Sep 10 16:03:06 systemd[1]: mysql.service: Start request repeated too quickly.
    Sep 10 16:03:06 systemd[1]: mysql.service: Failed with result 'exit-code'.
    Sep 10 16:03:06 systemd[1]: Failed to start MySQL Community Server.
    -- Subject: Unit mysql.service has failed
    -- Defined-By: systemd
    -- Support: http://www.ubuntu.com/support
    -- 
    -- Unit mysql.service has failed.
    -- 
    -- The result is RESULT.