一、首先查看主庫的數據文件信息：
SQL>set sqlprompt"_user'@'_connect_identifier>"
SYS@primarydb> select file#,name from v$datafile;
FILE# NAME
1 +DATADG/primarydb/datafile/system.270.785597071
2 +DATADG/primarydb/datafile/sysaux.269.785597073
3 +DATADG/primarydb/datafile/undotbs1.264.785597075
4 +DATADG/primarydb/datafile/users.262.785597077
5 +DATADG/primarydb/datafile/ggs.261.785597131
6 +DATADG/primarydb/datafile/ggs.259.785597479二、模擬故障發生
直接進入 asmcmd
ASMCMD>cd +datadg/primarydb/datafile
ASMCMD> rm -f users.262.785597077
ORA-15032: not all alterations performed
ORA-15028: ASM file '+datadg/primarydb/datafile/users.262.785597077' not dropped;
currently being accessed (DBD ERROR: OCIStmtExecute) ASM的文件保護機制還是挺強的，由於數據庫還是 open狀態,無法直接 rm操作, 關閉數據庫後重新刪除。
SYS@primarydb>shutdown immediate
ASMCMD> rm -f users.262.785597077
重新嘗試打開數據庫
SQL> startup
ORACLE instance started.
Total System Global Area 417546240 bytes
Fixed Size 2227072bytes
Variable Size 364905600bytes
Database Buffers 46137344bytes
Redo Buffers 4276224bytes
Database mounted.
ORA-01157: cannot identify/lock data file 4 - see DBWR trace file
ORA-01110: data file 4: '+DATADG/primarydb/datafile/users.262.785597077' 找不到數據文件了
嘗試能不能從重建數據文件恢復：
SQL> alter database create datafile
'+DATADG/primarydb/datafile/users.262.785597077'；Database altered.
SQL> alter database open;
alter database open
*
ERROR at line 1:
ORA-01190: control file or data file 4 is from before the last RESETLOGS
ORA-01110: data file 4: '+DATADG/primarydb/datafile/ users.262.785597077'
SQL>recover datafile 4;
ORA-00279: change 15286generated at 06/09/2012 18:39:26 needed for thread 1
ORA-00289: suggestion: +FRAD
ORA-00280: change 15286 for thread 1 is in sequence #1
Specify log: {<RET>=suggested | filename | AUTO | CANCEL}
ORA-00308: cannot open archived log '+FRADG'
ORA-17503: ksfdopn:2 Failed to open file +FRADG
ORA-15045: ASM file name '+FRADG' is not in reference form
users表空間是系統默認表空間，無法實現通過重建數據文件,再 recover的方式恢復數據文件；
三、利用 DG備庫恢復
通過拷貝 DG對應數據文件的方式恢復損壞的數據文件。
RMAN>backup as copy datafile 4 format '/oracle/users.262.785597077';
Starting backup at 2012-06-19 19:29:42
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=32 device type=DISK channel ORA_DISK_1:
starting datafile copy
input datafile file number=00004
name=+DATADG/standbydb/datafile/users.261.785540219
output file name=/oracle/users.262.785597077 tag=TAG20120619T192943 RECID=1 STAMP=786396584
channel ORA_DISK_1: datafile copy complete, elapsed time: 00:00:01 Finished backup at 2012-06-19 19:29:44 將 users.262.785597077從備庫 ftp到主庫
ASMCMD> cp /home/oracle/users.262.785597077 users.262.785597077
copying /home/oracle/users.262.785597077 ->
+datadg/primarydb/datafile/users.262.785597077
ASMCMD-08016: copy source->'/home/oracle/users.262.785597077' and
target->'+datadg/primarydb/datafile/users.262.785597077'failed ORA-15056: additional error message
ORA-15046: ASM filename '+datadg/primarydb/datafile/users.262.785597077' is not in single-file creation form
ORA-06512: at"SYS.X$DBMS_DISKGROUP", line 410
ORA-06512: at line 3 (DBD ERROR: OCIStmtExecute)
ASMCMD> cp /home/oracle/users.262.785597077 users
copying /home/oracle/users.262.785597077 ->+datadg/primarydb/datafile/users
ASM不允許手動創建後面跟 9位隨機數字的文件，沒辦法只有重命名了
重定向數據文件（如果是文件系統應就沒這個問題了）
SQL> alter database rename file '+DATADG/primarydb/datafile/users.262.785597077' to '+DATADG/primarydb/datafile/users';
Database altered.
SQL> recover datafile 4;
Media recovery complete.
SQL> alter database open;
數據庫恢復完畢！
如果是開啓歸檔之後創建的表空間，數據文件損壞後使用重建數據文件恢復（保證歸檔不丟）
SQL>set sqlprompt "_user'@'_connect_identifier>"
SYS@primarydb>createtablespace test datafile '/oracle/test01.dbf' size 10m;
Tablespace created.
SYS@primarydb>create user test identified by test default tablespace test;
User created.
SYS@primarydb>grantconnect,resource to test;
Grant succeeded.
TEST@primarydb>conn test/test
Connected.
TEST@primarydb> create table job ( name varchar2(80),offer date,department varchar2(80) ) tablespace TEST;
Table created.
TEST@primarydb>insert into job values('john','09/09/2009','系統集成部');
1 row created.
TEST@primarydb> commit;
TEST@primarydb> col name format a10
TEST@primarydb> set linesize 200
TEST@primarydb> select * from job;
NAME OFFER DEPARTMENT
john 0009-09-20 09:00:00 系統集成部
TEST@primarydb>conn /as sysdba
Connected.
SYS@primarydb>alter system switch logfile;
System altered. 在備份庫查看數據是否同步過來
SQL>setsqlprompt "_user'@'_connect_identifier>"
SYS@standbydb>conn test/test
Connected.
TEST@standbydb>col name format a10
TEST@standbydb>set linesize 200
TEST@standbydb>select * from job;
NAME OFFER DEPARTMENT
john 0009-09-20 09:00:00 系統集成部主庫上更新表
TEST@primarydb>update job set OFFER='2009-09-09 08:00:00';
TEST@primarydb> commit;
TEST@standbydb>select * from job;
NAME OFFER DEPARTMENT
john 2009-09-09 08:00:00 系統集成部製造故障，將新建的表空間數據文件 DD掉
rac1:/oracle$dd if=/dev/zero of=/oracle/lixz01.dbf bs=1024k count=10
查看 JOB表：
TEST@primarydb> select * from job;
ERROR at line 1:
ORA-01578: ORACLE datablock corrupted (file # 7, block # 138) ORA-01110: data file 7:'/oracle/test01.dbf'出現數據文件損壞報錯
重建數據文件：SYS@primarydb>alter database create datafile '/oracle/test01.dbf';
alter database createdatafile '/oracle/test01.dbf'
*
ERROR at line 1:
ORA-01182: cannot create database file 7 - file is in use or recovery ORA-01110: data file 7:'/oracle/test01.dbf'兩種處理辦法：
第一種：
SQL> alter database datafile 7 offline;
Database altered.
SQL> alterdatabase create datafile'/oracle/test01.dbf';
SQL> recover datafile 7;
Log applied.
Media recovery complete. 第二種：
SYS@primarydb>shutdown immediate
ORA-01122: database file 7 failed verification check ORA-01110: data file7: '/oracle/test01.dbf'
ORA-01210: data file header is media corrupt
SYS@primarydb> shutdown abort
ORACLE instance shut down.
SQL> startup mount;
ORACLE instance started.
Total System Global Area 417546240 bytes
Fixed Size 2227072bytes
Variable Size 364905600bytes
Database Buffers 46137344bytes
Redo Buffers 4276224bytes
Database mounted.
SQL> alterdatabase create datafile '/oracle/test01.dbf';
Database altered.
SQL> recover datafile 7;
ORA-00279: change519308 generated at 06/19/2012 20:39:43 needed for thread 1
ORA-00289: suggestion :+FRADG/primarydb/archivelog/2012_06_19/thread_1_seq_65.413.786401525
ORA-00280: change 519308 for thread 1 is in sequence #65
Specify log:{<RET>=suggested | filename | AUTO | CANCEL} AUTO
Log applied.
Media recovery complete.
SQL>alter database open;
Database altered.
SYS@primarydb> conn test/test
Connected.
SQL>alter database rename file '+DATADG/primarydb/datafile/users.262.785597077' to '+DATADG/primarydb/datafile/users';
Database altered.
SQL> recover datafile 4;
Media recovery complete.
SQL> alter database open;
TEST@primarydb>select * from job;
NAME OFFER DEPARTMENT
john 2009-09-09 08:00:00 系統集成部