2节点oracle 19c rac （19.8）, 操作系统 redhat 7.5
节点1，alert日志显示发生471错误，pmon终止了数据库实例，如下所示：
2020-12-18T10:49:24.500418+08:00
PMON (ospid: 20610): terminating the instance due to ORA error 471
2020-12-18T10:49:24.500618+08:00
Cause - ‘Instance is being terminated due to fatal process death (pid: 43, ospid: 20715, DBW6)’
2020-12-18T10:49:25.552511+08:00
Instance terminated by PMON, pid = 20610
2020-12-18T10:57:19.622108+08:00
操作系统自动重启了。 请专家帮忙分析下原因，及解决方法，感谢！！！