检查alert日志，发现如下错误：
2020-10-09 04:45:22.826000 +08:00
ORA-25455 encountered when generating server alert SMG-3503
2020-10-09 04:46:23.920000 +08:00
Errors in file /home/oracle/app/diag/rdbms/pos01/pos01/trace/pos01_mmon_23333.trc (incident=30172):
ORA-00600: internal error code, arguments: [keltenq-99], [21779], [ORA-21779: duration not active
], [], [], [], [], [], [], [], [], []
Incident details in: /home/oracle/app/diag/rdbms/pos01/pos01/incident/incdir_30172/pos01_mmon_23333_i30172.trc
2020-10-09 04:46:27.351000 +08:00
Use ADRCI or Support Workbench to package the incident.
See Note 411.1 at My Oracle Support for error and packaging details.
Dumping diagnostic data in directory=[cdmp_20201009044627], requested by (instance=1, osid=23333 (MMON)), summary=[incident=30172].
进程MMON及MMNL自动挂掉，无法自动启动。