删除文件，实例宕机？是的，ORA-63999 数据文件遭受介质故障

19c数据库正在运行中，如果从操作系统层面rm掉一个数据文件，则实例宕机

ARC2 (PID:2324): Archived Log entry 5 added for T-1.S-18 ID 0x605479f8 LAD:1
2021-11-12 12:20:39.524000 -08:00
Thread 1 cannot allocate new log, sequence 20
Checkpoint not complete
  Current log# 1 seq# 19 mem# 0: /u01/app/oracle/oradata/ORCL/redo01.log
2021-11-12 12:20:41.988000 -08:00
Errors in file /u01/app/oracle/diag/rdbms/orcl/orcl/trace/orcl_ckpt_2266.trc:
ORA-63999: data file suffered media failure
ORA-01116: error in opening database file 7
ORA-01110: data file 7: '/u01/app/oracle/oradata/ORCL/users01.dbf'
ORA-27041: unable to open file
Linux-x86_64 Error: 2: No such file or directory
Additional information: 3
Errors in file /u01/app/oracle/diag/rdbms/orcl/orcl/trace/orcl_ckpt_2266.trc:
ORA-63999: data file suffered media failure
ORA-01116: error in opening database file 7
ORA-01110: data file 7: '/u01/app/oracle/oradata/ORCL/users01.dbf'
ORA-27041: unable to open file
Linux-x86_64 Error: 2: No such file or directory
Additional information: 3
Errors in file /u01/app/oracle/diag/rdbms/orcl/orcl/trace/orcl_ckpt_2266.trc (incident=16961):
ORA-63999 [] [] [] [] [] [] [] [] [] [] [] []
Incident details in: /u01/app/oracle/diag/rdbms/orcl/orcl/incident/incdir_16961/orcl_ckpt_2266_i16961.trc
Errors in file /u01/app/oracle/diag/rdbms/orcl/orcl/trace/orcl_mz00_2781.trc:
ORA-01110: data file 7: '/u01/app/oracle/oradata/ORCL/users01.dbf'
ORA-01565: error in identifying file '/u01/app/oracle/oradata/ORCL/users01.dbf'
ORA-27037: unable to obtain file status
Linux-x86_64 Error: 2: No such file or directory
Additional information: 7
2021-11-12 12:20:43.451000 -08:00
USER (ospid: 2266): terminating the instance due to ORA error 63999
System state dump requested by (instance=1, osid=2266 (CKPT)), summary=[abnormal instance termination].
System State dumped to trace file /u01/app/oracle/diag/rdbms/orcl/orcl/trace/orcl_diag_2239.trc
Dumping diagnostic data in directory=[cdmp_20211112122043], requested by (instance=1, osid=2266 (CKPT)), summary=[abnormal instance termination].
2021-11-12 12:20:45.541000 -08:00
Instance terminated by USER, pid = 2266

这太不健壮了，所以还是让数据库容错能力恢复到原先吧

alter system set "_datafile_write_errors_crash_instance"=false;

这样的话，如果有个别文件出现问题，只在告警日志中报错，不至于整个数据库无法访问。
所有生产库都应该这样设置。