SQL> alter database open;
alter database open
*
ERROR at line 1:
ORA-03113: end-of-file on communication channel
Process ID: 10380
Session ID: 32 Serial number: 24360

跟踪日志错误提示如下：
[oracle@dg1 trace]$ tail -200f /u01/app/oracle/diag/rdbms/cndba/cndba/trace/alert_cndba.log

Errors in file /u01/app/oracle/diag/rdbms/cndba/cndba/trace/cndba_ora_10380.trc:
ORA-16014: log 3 sequence# 3 not archived, no available destinations
ORA-00312: online log 3 thread 1: '/u01/app/oracle/oradata/cndba/redo03.log'
2017-07-31T11:01:26.938354+08:00
USER (ospid: 10380): terminating the instance due to error 16014
2017-07-31T11:01:26.997422+08:00
System state dump requested by (instance=1, osid=10380), summary=[abnormal instance termination].
System State dumped to trace file /u01/app/oracle/diag/rdbms/cndba/cndba/trace/cndba_diag_10313_20170731110126.trc
2017-07-31T11:01:27.081110+08:00

错误信息提示：archive log 无法归档，而且报错信息看出是 redo03.log该日志文件被损坏了。

SQL> alter database clear unarchived logfile group 3;

Database altered.

SQL> shutdown immediate
ORA-01109: database not open


Database dismounted.
ORACLE instance shut down.
SQL> startup
ORACLE instance started.

Total System Global Area 1426063360 bytes
Fixed Size		    8792776 bytes
Variable Size		  889193784 bytes
Database Buffers	  520093696 bytes
Redo Buffers		    7983104 bytes
Database mounted.
Database opened.
SQL> show pdbs

    CON_ID CON_NAME			  OPEN MODE  RESTRICTED
---------- ------------------------------ ---------- ----------
	 2 PDB$SEED			  READ ONLY  NO
	 3 PDBCNDBA			  READ WRITE NO
	 5 PDBCNDBA2		  READ WRITE NO