Original address: https://blogs.oracle.com/database4cn/rmandataguardstandby
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Many customers who are using dataguard will encounter a difficult problem: one or more archived logs are lost due to network reasons or disk problems during the synchronization between the backup side and the main database, and the dataguard synchronization cannot continue. Many customers have chosen to restore the entire database and rebuild dataguard. If our source database is very large (more than 100G of data), we can actually choose a simpler and more efficient recovery method-restore the data on the standby side of dataguard through rman's incremental backup.
The specific recovery process is as follows:
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: The above one is the SCN number recorded in the control file, and the other is the SCN number recorded in the data file header. We need to choose the smaller SCN number (3162298) for backup.
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)