sqlplus / as sysdba
SQL> startup force
ORACLE instance started.

Total System Global Area 2147482944 bytes
Fixed Size                  9137472 bytes
Variable Size             520093696 bytes
Database Buffers         1610612736 bytes
Redo Buffers                7639040 bytes
Database mounted.
ORA-01113: file 1 needs media recovery
ORA-01110: data file 1: '/u02/oradata/CDB1/system01.dbf'


SQL> recover datafile '/u02/oradata/CDB1/system01.dbf'
ORA-00283: recovery session canceled due to errors
ORA-00742: Log read detects lost write in thread 1 sequence 424 block 78120
ORA-00312: online log 1 thread 1: '/u02/oradata/CDB1/redo01.log'