SYS@ bys3>shutdown immediate;
Database closed.
Database dismounted.
ORACLE instance shut down.
SYS@ bys3>startup
ORACLE instance started.
Total System Global Area 225996800 bytes
Fixed Size 1363692 bytes
Variable Size 150995220 bytes
Database Buffers 67108864 bytes
Redo Buffers 6529024 bytes
Database mounted.
ORA-01113: file 1 needs media recovery
ORA-01110: data file 1: '/u01/oradata/bys3/system01.dbf'
SYS@ bys3> recover datafile 1;
Media recovery complete.
SYS@ bys3>alter database open;
Database altered.
#############
2.如果丢失的是非SYSTEM/UNDO，则可以在线恢复：方法如下：
BYS@ bys3>alter database datafile 6 offline;Database altered.
BYS@ bys3>recover datafile 6;
Media recovery complete.
BYS@ bys3>alter database datafile 6 online;
Database altered.
################
3.UNDO的OFFLINE及恢复和上面一样：
SYS@ bys3>alter database datafile 3 offline;alter database datafile 3 offline
*
ERROR at line 1:
ORA-00603: ORACLE server session terminated by fatal error
ORA-00376: file 3 cannot be read at this time
ORA-01110: data file 3: '/u01/oradata/bys3/undotbs01.dbf'
ORA-00376: file 3 cannot be read at this time
ORA-01110: data file 3: '/u01/oradata/bys3/undotbs01.dbf'
ORA-00376: file 3 cannot be read at this time
Process ID: 15106
Session ID: 1 Serial number: 5
BYS@ bys3>update dept set deptno=22;
update dept set deptno=22
*
ERROR at line 1:
ORA-00604: error occurred at recursive SQL level 1
ORA-00376: file 3 cannot be read at this time
ORA-01110: data file 3: '/u01/oradata/bys3/undotbs01.dbf'
#########
4.控制文件误删除的恢复的上面数据文件的恢复方法基本一样：
[oracle@bys3 ~]$ rm -rf /u01/oradata/bys3/control*[oracle@bys3 ~]$ ps -ef|grep ckpt|grep -v grep ----注意这里查的 是CKPT进程。
oracle 15076 1 0 11:53 00:00:01 ora_ckpt_bys3
[oracle@bys3 ~]$ ll /proc/15076/fd
total 0
lr-x------ 1 oracle oinstall 64 Mar 7 12:12 0 -> /dev/null
l-wx------ 1 oracle oinstall 64 Mar 7 12:12 1 -> /dev/null
lrwx------ 1 oracle oinstall 64 Mar 7 12:12 10 -> /u01/app/oracle/product/11.2.0/dbhome_1/dbs/lkBYS3
lr-x------ 1 oracle oinstall 64 Mar 7 12:12 11 -> /u01/app/oracle/product/11.2.0/dbhome_1/rdbms/mesg/oraus.msb
l-wx------ 1 oracle oinstall 64 Mar 7 12:12 2 -> /dev/null
lrwx------ 1 oracle oinstall 64 Mar 7 12:12 256 -> /u01/oradata/bys3/control01.ctl (deleted)
lrwx------ 1 oracle oinstall 64 Mar 7 12:12 257 -> /u01/oradata/bys3/control02.ctl (deleted)
lr-x------ 1 oracle oinstall 64 Mar 7 12:12 3 -> /dev/null
lr-x------ 1 oracle oinstall 64 Mar 7 12:12 4 -> /dev/null
lr-x------ 1 oracle oinstall 64 Mar 7 12:12 5 -> /dev/null
lr-x------ 1 oracle oinstall 64 Mar 7 12:12 6 -> /u01/app/oracle/product/11.2.0/dbhome_1/rdbms/mesg/oraus.msb
lr-x------ 1 oracle oinstall 64 Mar 7 12:12 7 -> /proc/15076/fd
lr-x------ 1 oracle oinstall 64 Mar 7 12:12 8 -> /dev/zero
lrwx------ 1 oracle oinstall 64 Mar 7 12:12 9 -> /u01/app/oracle/product/11.2.0/dbhome_1/dbs/hc_bys3.dat
[oracle@bys3 ~]$ cp /proc/15076/fd/256 /u01/oradata/bys3/control01.ctl
[oracle@bys3 ~]$ cp /proc/15076/fd/257 /u01/oradata/bys3/control02.ctl
[oracle@bys3 ~]$ ls /u01/oradata/bys3/control*
/u01/oradata/bys3/control01.ctl /u01/oradata/bys3/control02.ctl
日志：
Fri Mar 07 12:12:04 2014
Errors in file /u01/diag/rdbms/bys3/bys3/trace/bys3_m000_15540.trc:
ORA-00210: cannot open the specified control file
ORA-00202: control file: '/u01/oradata/b