问题描述：
在启动数据库的时候报：ORA-03113: end-of-file on communication channel的错误。
SQL> startup
ORACLE instance started.
Total System Global Area 4275781632 bytes
Fixed Size 2260088 bytes
Variable Size 889193352 bytes
Database Buffers 3372220416 bytes
Redo Buffers 12107776 bytes
Database mounted.
ORA-03113: end-of-file on communication channel
Process ID: 27933
Session ID: 191 Serial number: 3
检查错误日志出现下面错误信息：
[node2:oracle:OARAC]cd /u01/app/diag/rdbms/orcl/OARAC/trace
[node2:oracle:OARAC]tail alert_OARAC.log
ORA-00341: log 1 of thread , wrong log # in header
ORA-00312: online log 3 thread 1: '/u01/app/oradata/orcl/redo03a.log'
Wed Feb 08 10:32:42 2023
ARC1 started with pid=22, OS id=28135
USER (ospid: 28131): terminating the instance due to error 341
Wed Feb 08 10:32:42 2023
System state dump requested by (instance=1, osid=28131), summary=[abnormal instance termination].
System State dumped to trace file /u01/app/diag/rdbms/orcl/OARAC/trace/OARAC_diag_28099_20230208103242.trc
Dumping diagnostic data in directory=[cdmp_20230208103242], requested by (instance=1, osid=28131), summary=[abnormal instance termination].
Instance terminated by USER, pid = 28131
原因分析：
自己在做测试，在操作系统中手动将数据库的一个重做日志组文件给删除了，然后重启数据库时报上面的错误信息。
[node2:oracle:OARAC]cd /u01/app/oradata/orcl/
[node2:oracle:OARAC]rm -rf redo03a.log
解决方案：
关闭数据库，将数据库启动到mount状态，然后删除对应的重做日志组，最后再打开数据库。
[node2:oracle:OARAC]sqlplus / as sysdba
SQL> shutdown immediate
SQL> startup mount
SQL> alter database drop logfile group 3;
SQL> alter database open;
