当 Active IQ Unified Manager 从较新版本还原到较旧版本时，MySQL 无法启动
适用于
- Active IQ Unified Manager 9.x ( AIQUM )
- OnCommand Unified Manager 9.x ( OCUM )
- Red Hat Enterprise Linux
- CentOS
问题
从 Unified Manager (UM) 恢复到 Unified Manager 的早期版本时，MySQL 无法启动。此 MySQL 启动失败也将导致以前版本的 UM 的新安装失败。
- 运行
systemctl status mysqld的错误为：
mysqld.service - MySQL Server
Loaded: loaded (/usr/lib/systemd/system/mysqld.service; enabled; vendor preset: disabled)
Active: failed (Result: start-limit) since Tue 2020-05-05 16:38:36 -07; 7min ago
Docs: man:mysqld(8)
http://dev.mysql.com/doc/refman/en/using-systemd.html
May 05 16:38:36 <server_name> systemd[1]: Failed to start MySQL Server.
May 05 16:38:36 <server_name> systemd[1]: Unit mysqld.service entered failed state.
May 05 16:38:36 <server_name> systemd[1]: mysqld.service failed.
May 05 16:38:36 <server_name> systemd[1]: mysqld.service holdoff time over, scheduling restart.
May 05 16:38:36 <server_name> systemd[1]: start request repeated too quickly for mysqld.service
May 05 16:38:36 <server_name> systemd[1]: Failed to start MySQL Server.
May 05 16:38:36 <server_name> systemd[1]: Unit mysqld.service entered failed state.
May 05 16:38:36 <server_name> systemd[1]: mysqld.service failed.
- 检查
/var/log/mysqld.log时，可以看到以下内容：
2020-05-05T00:21:13.687193Z 0 [ERROR] [FATAL] InnoDB: Table flags are 0 in the data dictionary but the flags in file ./ibdata1 are 0x4000!
2020-05-04 17:21:13 0x7f758b34e780 InnoDB: Assertion failure in thread 140142823401344 in file ut0ut.cc line 918
"Cannot boot server version 80021 on data directory built by version 80023. Downgrade is not supported"
在 UM 安装期间在 CLI 上看到的错误是：
Job for mysqld.service failed because the control process exited with error code. See "systemctl status mysqld.service" and "journalctl -xe" for details.
ERROR: MySQL pid missing after 600s, unable to continue.
Warning: %post(netapp-platform-base-9.5.0-2019.04.J68.x86_64) scriptlet failed, exit status 1
Non-fatal POSTIN scriptlet failure in rpm package netapp-platform-base-9.5.0-2019.04.J68.x86_64
FAILURE: netapp-platform-base package is installed, but in in a corrupt state. Install netapp-platform-base package and try again.