Al iniciar la base de datos te muestra este error
[oracle@oraserv1 ~]$ sqlplus / as sysdba
SQL*Plus: Release 11.2.0.1.0 Production on Wed Sep 11 14:48:35 2019
Copyright (c) 1982, 2009, Oracle. All rights reserved.
Connected to an idle instance.
SQL> startup
ORACLE instance started.
Total System Global Area 1653518336 bytes
Fixed Size 2213896 bytes
Variable Size 1308624888 bytes
Database Buffers 335544320 bytes
Redo Buffers 7135232 bytes
Database mounted.
ORA-03113: end-of-file on communication channel
Process ID: 15039
Session ID: 19 Serial number: 3
SOLUCION:
[oracle@oraserv1 ~]$ sqlplus /nlog
SQL> conn / as sysdba
SQL> startup nomount
ORACLE instance started.
Total System Global Area 1653518336 bytes
Fixed Size 2213896 bytes
Variable Size 1308624888 bytes
Database Buffers 335544320 bytes
Redo Buffers 7135232 bytes
SQL> alter database mount;
Database altered.
SQL> alter database clear unarchived logfile group 1;
Database altered.
SQL> alter database clear unarchived logfile group 2;
Database altered.
SQL> alter database clear unarchived logfile group 3;
Database altered.
SQL> alter database clear unarchived logfile group 4;
alter database clear unarchived logfile group 4
*
ERROR at line 1:
ORA-00359: logfile group 4 does not exist
SQL> shutdown immediate
ORA-01109: database not open
Database dismounted.
ORACLE instance shut down.
SQL> startup
ORACLE instance started.
Total System Global Area 1653518336 bytes
Fixed Size 2213896 bytes
Variable Size 1308624888 bytes
Database Buffers 335544320 bytes
Redo Buffers 7135232 bytes
Database mounted.
Database opened.