試用Rman可以實現數據塊級的數據恢復,在傳統恢復手段中即某個數據文件的一個數據塊被損壞,就造成整個數據文件無法試用,此時必
RMAN 實現數據塊恢復
試用Rman可以實現數據塊級的數據恢復,在傳統恢復手段中即某個數據文件的一個數據塊被損壞,就造成整個數據文件無法試用,此時必須通過備份恢復整個數據文件。顯然這樣的方法會會時間較長,而RMAN實現塊級恢復,如果某個數據文件的數據損壞,通過數據文件的完整備份就可以恢復數據塊。
案例:
數據庫是一個單實例Oracle數據庫,該庫的總大小有700G。
存儲設備使用華為存儲,備份設備使用希捷3T的移動硬盤。該數據庫無DG無OGG。備份策略為每周六0點全庫備份,周三0點1級差異備份其余時間為每天0點做2級差異備份。全庫備份大小為500G左右。
2.2 故障情況
本次故障原因是INSPUROA用戶在查詢EDOC_BASE_WORKFLOW表出現報錯。提示故障壞塊為datafile 5。報錯信息取至alter日志如下:
Reading datafile '/oradata/datafiles/oadb/oa01.dbf' for corruption at rdba: 0x016d4dd5 (file 5, block 2969045)
Reread (file 5, block 2969045) found same corrupt data (no logical check)
Tue Aug 18 10:53:51 2015
Corrupt Block Found
TSN = 6, TSNAME = OA
RFN = 5, BLK = 2969045, RDBA = 23940565
OBJN = 95690, OBJD = 95690, OBJECT = EDOC_BASE_WORKFLOW, SUBOBJECT =
SEGMENT OWNER = INSPUROA, SEGMENT TYPE = Table Segment
Tue Aug 18 10:55:03 2015
Hex dump of (file 5, block 2969045) in trace file /u01/app/oracle/diag/rdbms/oadb/oadb/trace/oadb_ora_4565.trc
Corrupt block relative dba: 0x016d4dd5 (file 5, block 2969045)
Bad header found during buffer read
Data in bad block:
type: 117 format: 0 rdba: 0x20206b73
last change scn: 0x2020.20202020 seq: 0x20 flg: 0x20
spare1: 0x64 spare2: 0x69 spare3: 0x0
consistency value in tail: 0x4d240601
check value in block header: 0x5f49
block checksum disabled
Reading datafile '/oradata/datafiles/oadb/oa01.dbf' for corruption at rdba: 0x016d4dd5 (file 5, block 2969045)
Reread (file 5, block 2969045) found same corrupt data (no logical check)
Tue Aug 18 10:55:03 2015
Corrupt Block Found
TSN = 6, TSNAME = OA
RFN = 5, BLK = 2969045, RDBA = 23940565
OBJN = 95690, OBJD = 95690, OBJECT = EDOC_BASE_WORKFLOW, SUBOBJECT =
SEGMENT OWNER = INSPUROA, SEGMENT TYPE = Table Segment
Tue Aug 18 10:57:29 2015
Hex dump of (file 5, block 2969045) in trace file /u01/app/oracle/diag/rdbms/oadb/oadb/trace/oadb_ora_21708.trc
Corrupt block relative dba: 0x016d4dd5 (file 5, block 2969045)
Bad header found during buffer read
Data in bad block:
type: 117 format: 0 rdba: 0x20206b73
last change scn: 0x2020.20202020 seq: 0x20 flg: 0x20
spare1: 0x64 spare2: 0x69 spare3: 0x0
consistency value in tail: 0x4d240601
check value in block header: 0x5f49
block checksum disabled
分析原因
觀察存儲,無報錯警告,初步懷疑邏輯壞塊
執行修復
根據報錯信息
Reading datafile '/oradata/datafiles/oadb/oa01.dbf' for corruption at rdba: 0x016d4dd5 (file 5, block 2969045)
Reread (file 5, block 2969045) found same corrupt data (no logical check)
Corrupt Block Found
TSN = 6, TSNAME = OA
RFN = 5, BLK = 2969045, RDBA = 23940565
OBJN = 95690, OBJD = 95690, OBJECT = EDOC_BASE_WORKFLOW, SUBOBJECT =
SEGMENT OWNER = INSPUROA, SEGMENT TYPE = Table Segment
確定數據文件 datafile 5,oa01.dbf出現壞塊現象
查看壞塊信息:
SQL> select * from v$database_block_corruption;
FILE# BLOCK# BLOCKS CORRUPTION_CHANGE# CORRUPTIO
---------- ---------- ---------- ------------------ ---------
5 2969045 1 0 CORRUPT
確定壞塊為2969045號
檢查備份日志(增量,全量)是否完整備份
檢查備份datafile 5 是否完整
RMAN> backup validate datafile 5;
Starting backup at 18-AUG-15
using target database control file instead of recovery catalog
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=982 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=00005 name=/oradata/datafiles/oadb/oa01.dbf
channel ORA_DISK_1: backup set complete, elapsed time: 00:05:35
List of Datafiles
=================
File Status Marked Corrupt Empty Blocks Blocks Examined High SCN
---- ------ -------------- ------------ --------------- ----------
5 FAILED 0 1840 4190720 9484751217293
File Name: /oradata/datafiles/oadb/oa01.dbf
Block Type Blocks Failing Blocks Processed
---------- -------------- ----------------
Data 0 2842014
Index 0 182983
Other 1 1163883
validate found one or more corrupt blocks
See trace file /u01/app/oracle/diag/rdbms/oadb/oadb/trace/oadb_ora_13513.trc for details
Finished backup at 18-AUG-15
執行修復
使用RMAN工具
RMAN> blockrecover datafile 5 block 2969045;
Starting recover at 18-AUG-15
using channel ORA_DISK_1
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