如何增量備份恢復dataguard中standby端的數據

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這篇文章主要講解了“如何增量備份恢復 dataguard 中 standby 端的數據”，文中的講解內容簡單清晰，易于學習與理解，下面請大家跟著丸趣 TV 小編的思路慢慢深入，一起來研究和學習“如何增量備份恢復 dataguard 中 standby 端的數據”吧！

很多正在使用 dataguard 的客戶，都會遇到一個棘手的問題：在備份端與主庫同步的過程中由于網絡原因或磁盤問題導致一個或多個歸檔日志丟失，進而 dataguard 同步無法繼續。很多客戶都選擇了重新全庫恢復，并重新搭建 dataguard。如果我們的源數據庫非常大（超過 100G 的數據量），其實可以選擇一種更簡便并高效的恢復方法 – 通過 rman 的增量備份恢復 dataguard 中 standby 端的數據。

具體恢復過程如下：
1) Stop the managed recovery process (MRP) on the STANDBY database
SQL ALTER DATABASE RECOVER MANAGED STANDBY DATABASE CANCEL;
2) Determine the SCN of the STANDBY database.
SQL SELECT CURRENT_SCN FROM V$DATABASE;
CURRENT_SCN
————–
3164433
SQL select min(checkpoint_change#) from v$datafile_header
where file# not in (select file# from v$datafile where enabled = READ ONLY
MIN(F.FHSCN)
—————-
3162298
comment: 上面一個為控制文件中記錄的 SCN 號，另一個為數據文件頭記錄的 SCN 號，我們需要選擇較小 SCN 號（3162298）的來備份。
3) Take an incremental backup of the PRIMARY database
RMAN BACKUP INCREMENTAL FROM SCN 3162298 DATABASE FORMAT /tmp/ForStandby_%U tag FORSTANDBY
4) Transfer all backup sets to STANDBY server
scp /tmp/ForStandby_* standby:/tmp
5) Catalog the backups in STANDBY controlfile.
RMAN CATALOG START WITH /tmp/ForStandby
6) Recover the STANDBY database with the cataloged incremental backup:
RMAN RECOVER DATABASE NOREDO;
7) In RMAN, connect to the PRIMARY database and create a standby control file backup:
RMAN BACKUP CURRENT CONTROLFILE FOR STANDBY FORMAT /tmp/ForStandbyCTRL.bck
8) Copy the standby control file backup to the STANDBY system.
9) Capture datafile information in STANDBY database.
We now need to refresh the standby controlfile from primary controlfile (for standby) backup. However, since the datafile names are likely different than primary, let s save the name of datafiles on standby first, which we can refer after restoring controlfile from primary backup to verify if there is any discrepancy. Run below query from Standby and save results for further use.
10) From RMAN, connect to STANDBY database and restore the standby control file:
RMAN SHUTDOWN IMMEDIATE ;
RMAN STARTUP NOMOUNT;
RMAN RESTORE STANDBY CONTROLFILE FROM /tmp/ForStandbyCTRL.bck
11) Shut down the STANDBY database and startup mount:
RMAN SHUTDOWN;
RMAN STARTUP MOUNT;
scp /tmp/ForStandbyCTRL.bck standby:/tmp
12) Catalog datafiles in STANDBY if location/name of datafiles is different
Since the controlfile is restored from PRIMARY the datafile locations in STANDBY controlfile will be same as PRIMARY database, if the directory structure is different between the standby and primary or you are using Oracle managed file names, catalog the datafiles in STANDBY will do the necessary rename operations. If the primary and standby have identical structure and datafile names, this step can be skipped.
Perform the below step in STANDBY for each diskgroup where the datafile directory structure between primary and standby are different.
RMAN CATALOG START WITH +DATA/mystd/datafile/
To determine if any files have been added to Primary since the standby current scn:
SQL SELECT FILE#, NAME FROM V$DATAFILE WHERE CREATION_CHANGE# 3162298
If the above query returns with 0 zero rows, you can switch the datafiles. This will rename the datafiles to its correct name at the standby site:
RMAN SWITCH DATABASE TO COPY;
datafile 1 switched to datafile copy +DATA/mystd/datafile/system.297.688213333
datafile 2 switched to datafile copy +DATA/mystd/datafile/undotbs1.268.688213335
datafile 3 switched to datafile copy +DATA/mystd/datafile/sysaux.267.688213333
13) Configure the STANDBY database to use flashback (optional)
SQL ALTER DATABASE FLASHBACK OFF;
SQL ALTER DATABASE FLASHBACK ON;
14) On STANDBY database, clear all standby redo log groups:
SQL ALTER DATABASE CLEAR LOGFILE GROUP 1;
SQL ALTER DATABASE CLEAR LOGFILE GROUP 2;
SQL ALTER DATABASE CLEAR LOGFILE GROUP 3;
….
15) On the STANDBY database, start the MRP
SQL ALTER DATABASE RECOVER MANAGED STANDBY DATABASE DISCONNECT;
For more detailed info:
Steps to perform for Rolling Forward a Physical Standby Database using RMAN Incremental Backup. (Doc ID 836986.1)

感謝各位的閱讀，以上就是“如何增量備份恢復 dataguard 中 standby 端的數據”的內容了，經過本文的學習后，相信大家對如何增量備份恢復 dataguard 中 standby 端的數據這一問題有了更深刻的體會，具體使用情況還需要大家實踐驗證。這里是丸趣 TV，丸趣 TV 小編將為大家推送更多相關知識點的文章，歡迎關注！

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