我刚刚在 Ubuntu 20.04 服务器上从 mysql 迁移到 mariadb apt install mariadb-server。安装顺利结束，但 mariadb-server 没有启动。
这是该命令的输出：
service mariadb start; journalctl -xe
Job for mariadb.service failed because the control process exited with error code.
See "systemctl status mariadb.service" and "journalctl -xe" for details.
-- Defined-By: systemd
-- Support: http://www.ubuntu.com/support
--
-- A start job for unit mariadb.service has begun execution.
--
-- The job identifier is 22456.
Nov 04 13:46:18 Socrates mysqld[18047]: 2020-11-04 13:46:18 0 [Note] /usr/sbin/mysqld (mysqld 10.3.>
Nov 04 13:46:18 Socrates mysqld[18047]: 2020-11-04 13:46:18 0 [Warning] Could not increase number o>
Nov 04 13:46:19 Socrates audit[18047]: AVC apparmor="DENIED" operation="sendmsg" info="Failed name >
Nov 04 13:46:19 Socrates kernel: audit: type=1400 audit(1604493979.310:19): apparmor="DENIED" opera>
Nov 04 13:46:19 Socrates audit[18047]: AVC apparmor="DENIED" operation="sendmsg" info="Failed name >
Nov 04 13:46:19 Socrates kernel: audit: type=1400 audit(1604493979.530:20): apparmor="DENIED" opera>
Nov 04 13:46:19 Socrates systemd[1]: mariadb.service: Main process exited, code=exited, status=1/FA>
-- Subject: Unit process exited
-- Defined-By: systemd
-- Support: http://www.ubuntu.com/support
--
-- An ExecStart= process belonging to unit mariadb.service has exited.
--
-- The process' exit code is 'exited' and its exit status is 1.
Nov 04 13:46:19 Socrates systemd[1]: mariadb.service: Failed with result 'exit-code'.
-- Subject: Unit failed
-- Defined-By: systemd
-- Support: http://www.ubuntu.com/support
--
-- The unit mariadb.service has entered the 'failed' state with result 'exit-code'.
Nov 04 13:46:19 Socrates systemd[1]: Failed to start MariaDB 10.3.25 database server.
-- Subject: A start job for unit mariadb.service has failed
-- Defined-By: systemd
-- Support: http://www.ubuntu.com/support
--
-- A start job for unit mariadb.service has finished with a failure.
--
-- The job identifier is 22456 and the job result is failed.
这是我在 /var/log/mysql/error.log 中发现的内容：
2020-11-04 14:17:50 0 [ERROR] InnoDB: Invalid flags 0x4000 in ./ibdata1
2020-11-04 14:17:50 0 [ERROR] InnoDB: Plugin initialization aborted with error Data structure corruption
2020-11-04 14:17:50 0 [Note] InnoDB: Starting shutdown...
2020-11-04 14:17:51 0 [ERROR] Plugin 'InnoDB' init function returned error.
2020-11-04 14:17:51 0 [ERROR] Plugin 'InnoDB' registration as a STORAGE ENGINE failed.
2020-11-04 14:17:51 0 [Note] Plugin 'FEEDBACK' is disabled.
2020-11-04 14:17:51 0 [ERROR] Could not open mysql.plugin table. Some plugins may be not loaded
2020-11-04 14:17:51 0 [ERROR] Unknown/unsupported storage engine: InnoDB
2020-11-04 14:17:51 0 [ERROR] Aborting