만약 users 테이블스페이스를 구성하는 datafile이 유실 되었다면

1) 에러 메시지
SQL> startup
ORA-01157: cannot identify/lock data file 3 - see DBWR trace file
ORA-01110: data file 3: '/opt/oracle/dbs/users01.dbf'

SQL> shutdown abort
SQL> exit

2) Recovery 시작
$cp $HOME/BACKUP/*.ctl $HOME/dbs/
$cp $HOME/BACKUP/*.dbf $HOME/dbs/
$sqlplus '/as sysdba'

SQL> startup
Database mounted
ORA-00314: log 1 of thread 1, expected sequence# doesn't match
ORA-00312: online log 1 thread 1: '/opt/oracle/oradata/log1a.rdo'
ORA-00312: online log 1 thread 1: '/opt/oracle/oradata/log1b.rdo'

SQL> select * from v$log;
sequence number가 30,31 이라하자

SQL> recover database until cancel;
SQL> alter database open resetlogs;
SQL> select * from v$log;
sequence number가 0과 1로 바뀜