在有些情况下,我们仅有一份rman备份，而这个时候rman 备份有出现坏块，使得我们的还原/恢复工作无法继续下去，导致数据大量丢失。我们可以通过设置event 19548/19549来跳过坏块,***程度抢救数据。
rman备份数据文件
- C:\Users\XIFENFEI>rman target /
- Recovery Manager: Release 11.2.0.3.0 - Production on Thu Jun 6 20:31:19 2013
- Copyright (c) 1982, 2011, Oracle and/or its affiliates. All rights reserved.
- connected to target database: XIFENFEI (DBID=1422012639)
- RMAN> backup tablespace users format 'f:/users_bak.rman';
- Starting backup at 06-JUN-13
- using target database control file instead of recovery catalog
- allocated channel: ORA_DISK_1
- channel ORA_DISK_1: SID=197 device type=DISK
- channel ORA_DISK_1: starting full datafile backup set
- channel ORA_DISK_1: specifying datafile(s) in backup set
- input datafile file number=00004 name=E:\ORACLE\ORADATA\XIFENFEI\USERS01.DBF
- channel ORA_DISK_1: starting piece 1 at 06-JUN-13
- channel ORA_DISK_1: finished piece 1 at 06-JUN-13
- piece handle=F:\USERS_BAK.RMAN tag=TAG20130606T203154 comment=NONE
- channel ORA_DISK_1: backup set complete, elapsed time: 00:00:03
- Finished backup at 06-JUN-13
切换归档日志
- SQL> alter system switch logfile;
- System altered.
- SQL> /
- System altered.
- SQL> /
- System altered.
- SQL> archive log list;
- Database log mode Archive Mode
- Automatic archival Enabled
- Archive destination E:\oracle\product\11.2.0\dbhome_1\RDBMS
- Oldest online log sequence 95
- Next log sequence to archive 97
- Current log sequence 97
重命名数据文件
- SQL> shutdown immediate
- Database closed.
- Database dismounted.
- ORACLE instance shut down.
- --------------------------------------
- e:\oracle\oradata\XIFENFEI>move USERS01.DBF USERS01_bak.DBF
- 移动了 1 个文件。
- --------------------------------------
- SQL> startup
- ORACLE instance started.
- Total System Global Area 418484224 bytes
- Fixed Size 1385052 bytes
- Variable Size 327159204 bytes
- Database Buffers 83886080 bytes
- Redo Buffers 6053888 bytes
- Database mounted.
- ORA-01157: cannot identify/lock data file 4 - see DBWR trace file
- ORA-01110: data file 4: 'E:\ORACLE\ORADATA\XIFENFEI\USERS01.DBF'
#p#
破坏备份集
破坏前
破坏后
这里很明显,我通过ue把rman备份集中的T修改为了A,肯定破坏了文件,使之出现坏块
rman还原数据文件
- C:\Users\XIFENFEI>rman target /
- Recovery Manager: Release 11.2.0.3.0 - Production on Thu Jun 6 21:02:41 2013
- Copyright (c) 1982, 2011, Oracle and/or its affiliates. All rights reserved.
- connected to target database: XIFENFEI (DBID=1422012639, not open)
- RMAN> restore datafile 4;
- Starting restore at 06-JUN-13
- using target database control file instead of recovery catalog
- allocated channel: ORA_DISK_1
- channel ORA_DISK_1: SID=63 device type=DISK
- channel ORA_DISK_1: starting datafile backup set restore
- channel ORA_DISK_1: specifying datafile(s) to restore from backup set
- channel ORA_DISK_1: restoring datafile 00004 to E:\ORACLE\ORADATA\XIFENFEI\USERS
- 01.DBF
- channel ORA_DISK_1: reading from backup piece F:\USERS_BAK.RMAN
- channel ORA_DISK_1: ORA-19870: error while restoring backup piece F:\USERS_BAK.R
- MAN
- ORA-19612: datafile 4 not restored due to missing or corrupt data
- failover to previous backup
- creating datafile file number=4 name=E:\ORACLE\ORADATA\XIFENFEI\USERS01.DBF
- Finished restore at 06-JUN-13
这里可以清晰的看到rman报ORA-19612错误，restore 失败,alert日志为：
- Thu Jun 06 21:02:31 2013
- ALTER DATABASE OPEN
- Errors in file E:\ORACLE\diag\rdbms\xifenfei\xff\trace\xff_dbw0_7400.trc:
- ORA-01157: ????/?????? 4 - ??? DBWR ????
- ORA-01110: ???? 4: 'E:\ORACLE\ORADATA\XIFENFEI\USERS01.DBF'
- ORA-27041: ??????
- OSD-04002: unable to open file
- O/S-Error: (OS 2) 系统找不到指定的文件。
- Errors in file E:\ORACLE\diag\rdbms\xifenfei\xff\trace\xff_ora_4272.trc:
- ORA-01157: cannot identify/lock data file 4 - see DBWR trace file
- ORA-01110: data file 4: 'E:\ORACLE\ORADATA\XIFENFEI\USERS01.DBF'
- ORA-1157 signalled during: ALTER DATABASE OPEN...
- Thu Jun 06 21:02:33 2013
- Checker run found 1 new persistent data failures
- Thu Jun 06 21:03:23 2013
- Corrupt block 101 found during reading backup piece, file=F:\USERS_BAK.RMAN, corr_type=3
- Reread of blocknum=101, file=F:\USERS_BAK.RMAN, found same corrupt data
- Reread of blocknum=101, file=F:\USERS_BAK.RMAN, found same corrupt data
- Reread of blocknum=101, file=F:\USERS_BAK.RMAN, found same corrupt data
- Reread of blocknum=101, file=F:\USERS_BAK.RMAN, found same corrupt data
- Reread of blocknum=101, file=F:\USERS_BAK.RMAN, found same corrupt data
- Continuing reading piece F:\USERS_BAK.RMAN, no other copies available.
rman备份集有坏块，导致rman还原无法正常进行下去,还原后的数据文件大小。
#p#
观察已经正常还原出来数据文件情况
- SQL> select CHECKPOINT_CHANGE#,file# from v$datafile_header;
- CHECKPOINT_CHANGE# FILE#
- ------------------ ----------
- 1571582 1
- 1571582 2
- 1571582 3
- 18379 4
- 1571582 5
- 1571582 6
- 1571582 7
- SQL> recover database datafile 4 ;
- ORA-00274: illegal recovery option DATAFILE
- SQL> recover datafile 4;
- ORA-00279: change 18379 generated at 01/20/2013 17:13:56 needed for thread 1
- ORA-00289: suggestion :
- E:\ORACLE\PRODUCT\11.2.0\DBHOME_1\RDBMS\ARC0000000001_0805223583.0001
- ORA-00280: change 18379 for thread 1 is in sequence #1
- Specify log: {<RET>=suggested | filename | AUTO | CANCEL}
rman只是还原了很小的一部分文件,做恢复提示需要从归档日志seq 1开始(某些情况可能需要其他归档,总之不是正常情况),证明rman还原异常
设置event事件还原
- SQL> shutdown abort;
- ORACLE instance shut down.
- SQL> startup pfile='e:/pfile.txt' mount;
- ORACLE instance started.
- Total System Global Area 418484224 bytes
- Fixed Size 1385052 bytes
- Variable Size 327159204 bytes
- Database Buffers 83886080 bytes
- Redo Buffers 6053888 bytes
- Database mounted.
- SQL> show parameter event;
- NAME TYPE VALUE
- ------------------------------------ ----------- ------------------------------
- event string 19548 trace name context forev
- er, 19549 trace name context f
- orever
- Event 19548:This will attempt to restore content of the corrupted block if it is possible.
- Event 19549:This will suppress erroring out during restore
rman还原数据文件
- RMAN> restore datafile 4;
- Starting restore at 06-JUN-13
- using target database control file instead of recovery catalog
- allocated channel: ORA_DISK_1
- channel ORA_DISK_1: SID=63 device type=DISK
- channel ORA_DISK_1: starting datafile backup set restore
- channel ORA_DISK_1: specifying datafile(s) to restore from backup set
- channel ORA_DISK_1: restoring datafile 00004 to E:\ORACLE\ORADATA\XIFENFEI\USERS
- 01.DBF
- channel ORA_DISK_1: reading from backup piece F:\USERS_BAK.RMAN
- channel ORA_DISK_1: piece handle=F:\USERS_BAK.RMAN tag=TAG20130606T203154
- channel ORA_DISK_1: restored backup piece 1
- channel ORA_DISK_1: restore complete, elapsed time: 00:00:35
- Finished restore at 06-JUN-13
这里证明数据库rman有坏块通过rman还原成功,alert日志提示如下：
- Thu Jun 06 21:29:53 2013
- WARNING: The block that appears to be block number 100
- in file 4 is corrupt in backup piece F:\USERS_BAK.RMAN.
- Such blocks would usually be formatted as empty
- in the restored file, but event 19548 has been
- set to include the block as-is in the restored
- file.
- Corrupt block 102 found during reading backup piece, file=F:\USERS_BAK.RMAN, corr_type=-2
- Reread of blocknum=102, file=F:\USERS_BAK.RMAN, found same corrupt data
- Reread of blocknum=102, file=F:\USERS_BAK.RMAN, found same corrupt data
- Reread of blocknum=102, file=F:\USERS_BAK.RMAN, found same corrupt data
- Reread of blocknum=102, file=F:\USERS_BAK.RMAN, found same corrupt data
- Reread of blocknum=102, file=F:\USERS_BAK.RMAN, found same corrupt data
- Continuing reading piece F:\USERS_BAK.RMAN, no other copies available.
- …………
- Corrupt block 258 found during reading backup piece, file=F:\USERS_BAK.RMAN, corr_type=-2
- Reread of blocknum=258, file=F:\USERS_BAK.RMAN, found same corrupt data
- Reread of blocknum=258, file=F:\USERS_BAK.RMAN, found same corrupt data
- Reread of blocknum=258, file=F:\USERS_BAK.RMAN, found same corrupt data
- Reread of blocknum=258, file=F:\USERS_BAK.RMAN, found same corrupt data
- Reread of blocknum=258, file=F:\USERS_BAK.RMAN, found same corrupt data
- Continuing reading piece F:\USERS_BAK.RMAN, no other copies available.
- WARNING: some data in the backup of file 4 was missing
- or corrupt. Event 19549 has been set to allow
- the file to be restored anyway.
- backup header block count: 5369
- backup actual block count: 5212
- backup header checksum: -218250743
- backup actual checksum: 1442665538
- Full restore complete of datafile 4 E:\ORACLE\ORADATA\XIFENFEI\USERS01.DBF. Elapsed time: 0:00:25
- checkpoint is 1570136
- last deallocation scn is 1508457
这里rman还原依然遇到很多坏块,但是均跳过坏块,还是完整的恢复出来的数据文件(大小)。
#p#
rman还原数据文件
- RMAN> recover datafile 4;
- Starting recover at 06-JUN-13
- using channel ORA_DISK_1
- starting media recovery
- archived log for thread 1 with sequence 94 is already on disk as file E:\ORACLE\
- PRODUCT\11.2.0\DBHOME_1\RDBMS\ARC0000000094_0805223583.0001
- archived log for thread 1 with sequence 95 is already on disk as file E:\ORACLE\
- PRODUCT\11.2.0\DBHOME_1\RDBMS\ARC0000000095_0805223583.0001
- archived log for thread 1 with sequence 96 is already on disk as file E:\ORACLE\
- PRODUCT\11.2.0\DBHOME_1\RDBMS\ARC0000000096_0805223583.0001
- archived log file name=E:\ORACLE\PRODUCT\11.2.0\DBHOME_1\RDBMS\ARC0000000094_080
- 5223583.0001 thread=1 sequence=94
- media recovery complete, elapsed time: 00:00:00
- Finished recover at 06-JUN-13
这里可以明显的看到在recover过程中数据库应用的是备份后的所有归档,数据文件是正常被还原出来(坏块除外)。
查询对象
- SQL> alter database open;
- Database altered.
- SQL> conn test/test
- Connected.
- SQL> select * from tab;
- TNAME TABTYPE CLUSTERID
- ------------------------------ ------- ----------
- STB101 TABLE
- SQL> select count(*) from stb101;
- select count(*) from stb101
- *
- ERROR at line 1:
- ORA-08103: object no longer exists
dbv检查坏块
- e:\oracle\oradata\XIFENFEI>dbv file=USERS01.DBF
- DBVERIFY: Release 11.2.0.3.0 - Production on Thu Jun 6 23:59:49 2013
- Copyright (c) 1982, 2011, Oracle and/or its affiliates. All rights reserved.
- DBVERIFY - Verification starting : FILE = E:\ORACLE\ORADATA\XIFENFEI\USERS01.DBF
- Page 100 is marked corrupt
- Corrupt block relative dba: 0x01000064 (file 4, block 100)
- Bad check value found during dbv:
- Data in bad block:
- type: 30 format: 2 rdba: 0x01000064
- last change scn: 0x0000.00004890 seq: 0x1 flg: 0x04
- spare1: 0x0 spare2: 0x0 spare3: 0x0
- consistency value in tail: 0x48901e01
- check value in block header: 0x8311
- computed block checksum: 0x20
- DBVERIFY - Verification complete
- Total Pages Examined : 12320
- Total Pages Processed (Data) : 4952
- Total Pages Failing (Data) : 0
- Total Pages Processed (Index): 0
- Total Pages Failing (Index): 0
- Total Pages Processed (Other): 7069
- Total Pages Processed (Seg) : 0
- Total Pages Failing (Seg) : 0
- Total Pages Empty : 298
证明设置了event之后，rman确实跳过了备份集中的坏块,而且是直接还原了坏块内容,证明了event 19548和19549作用。
补充说明
在非特殊情况下强烈不建议设置相关event跳过rman中的坏块来还原/恢复数据库,这样将对数据的丢失,甚至数据库是否可以正常open不好评估,rman备份重要,确保rman备份可用也很重要。
