SQL> startup
ORACLE instance started.
Total System Global Area 914358272 bytes
Fixed Size 2088184 bytes
Variable Size 528483080 bytes
Database Buffers 377487360 bytes
Redo Buffers 6299648 bytes
Database mounted.
ORA-01157: cannot identify/lock data file 8 - see DBWR trace file
ORA-01110: data file 8: '/var/opt/gssyneeadb/gssy_neeadb.dbf'
SQL> ALTER SYSTEM SET "_allow_resetlogs_corruption"=TRUE SCOPE=SPFILE;
System altered.
SQL> shutdown
ORA-01109: database not open
Database dismounted.
ORACLE instance shut down.
SQL> startup mount
ORACLE instance started.
Total System Global Area 914358272 bytes
Fixed Size 2088184 bytes
Variable Size 528483080 bytes
Database Buffers 377487360 bytes
Redo Buffers 6299648 bytes
Database mounted.
SQL> alter database datafile '/var/opt/gssyneeadb/gssy_neeadb.dbf' offline drop;
Database altered.
SQL> shutdown
ORA-01109: database not open
Database dismounted.
ORACLE instance shut down.
SQL> startup
ORACLE instance started.
Total System Global Area 914358272 bytes
Fixed Size 2088184 bytes
Variable Size 528483080 bytes
Database Buffers 377487360 bytes
Redo Buffers 6299648 bytes
Database mounted.
Database opened.
SQL>