Step by step - Rolling Forward a Physical Standby Database using RMAN Incremental Backup

1) Stop the managed recovery process (MRP) on the STANDBY database

SQL> ALTER DATABASE RECOVER MANAGED STANDBY DATABASE CANCEL;

Note:  For the remaining steps, the standby database must be in a MOUNT state.  

2) Determine the SCN of the STANDBY database.

On the standby database, find the SCN which will be used for the incremental backup at the primary database:

You need to use the 'lowest SCN' from the queries below:

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

You need to use the 'lowest SCN' from the queries, in this example is SCN: 3162298.  Therefore, From the above you need to backup from SCN 3162298

3) Take an incremental backup of the PRIMARY database

In RMAN, connect to the primary database and create an incremental backup from the SCN derived in the previous step:

RMAN> BACKUP INCREMENTAL FROM SCN 3162298 DATABASE FORMAT '/tmp/ForStandby_%U' tag 'FORSTANDBY';

4) Transfer all backup sets to STANDBY server

All backups created by step #3 must be transferred from the primary to the standby system.  If the backup is written to NFS device, this step can be skipped.

  

scp /tmp/ForStandby_* standby:/tmp

5) Catalog the backups in STANDBY controlfile.

In order for the standby database to know about the backups, catalog the backup pieces on the STANDBY database. 

RMAN> CATALOG START WITH '/tmp/ForStandby';

using target database control file instead of recovery catalog

searching for all files that match the pattern /tmp/ForStandby

List of Files Unknown to the Database

=====================================

File Name: /tmp/ForStandby_2lkglss4_1_1

File Name: /tmp/ForStandby_2mkglst8_1_1

Do you really want to catalog the above files (enter YES or NO)? YES

cataloging files...

cataloging done

List of Cataloged Files

=======================

File Name: /tmp/ForStandby_2lkglss4_1_1

File Name: /tmp/ForStandby_2mkglst8_1_1

6) Recover the STANDBY database with the cataloged incremental backup:

RMAN> RECOVER DATABASE NOREDO;

starting recover at 03-JUN-09

allocated channel: ORA_DISK_1

channel ORA_DISK_1: sid=28 devtype=DISK

channel ORA_DISK_1: starting incremental datafile backupset restore

channel ORA_DISK_1: specifying datafile(s) to restore from backup set

destination for restore of datafile 00001: +DATA/mystd/datafile/system.297.688213333

destination for restore of datafile 00002: +DATA/mystd/datafile/undotbs1.268.688213335

destination for restore of datafile 00003: +DATA/mystd/datafile/sysaux.267.688213333

channel ORA_DISK_1: reading from backup piece /tmp/ForStandby_2lkglss4_1_1

channel ORA_DISK_1: restored backup piece 1

piece handle=/tmp/ForStandby_2lkglss4_1_1 tag=FORSTANDBY

channel ORA_DISK_1: restore complete, elapsed time: 00:00:02

Finished recover at 03-JUN-09

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. 

scp /tmp/ForStandbyCTRL.bck standby:/tmp

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.

spool datafile_names_step8.txt

set lines 200

col name format a60

select file#, name from v$datafile order by file# ;

spool off

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';

Starting restore at 03-JUN-09

using target database control file instead of recovery catalog

allocated channel: ORA_DISK_1

channel ORA_DISK_1: sid=36 devtype=DISK

channel ORA_DISK_1: restoring control file

channel ORA_DISK_1: restore complete, elapsed time: 00:00:07

output filename=+DATA/mystd/controlfile/current.257.688583989

Finished restore at 03-JUN-09

11) Shut down the STANDBY database and startup mount:

RMAN> SHUTDOWN;

RMAN> STARTUP MOUNT;

12) Catalog datafiles in STANDBY if location/name of datafiles is different

Note:  We recommend checking the incarnation for primary and standby before completing this step.

example:  RMAN> list incarnation;

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/';

List of Files Unknown to the Database

=====================================

File Name: +data/mystd/DATAFILE/SYSTEM.309.685535773

File Name: +data/mystd/DATAFILE/SYSAUX.301.685535773

File Name: +data/mystd/DATAFILE/UNDOTBS1.302.685535775

File Name: +data/mystd/DATAFILE/SYSTEM.297.688213333

File Name: +data/mystd/DATAFILE/SYSAUX.267.688213333

File Name: +data/mystd/DATAFILE/UNDOTBS1.268.688213335

Do you really want to catalog the above files (enter YES or NO)? YES

cataloging files...

cataloging done

List of Cataloged Files

=======================

File Name: +data/mystd/DATAFILE/SYSTEM.297.688213333

File Name: +data/mystd/DATAFILE/SYSAUX.267.688213333

File Name: +data/mystd/DATAFILE/UNDOTBS1.268.688213335

If any datafiles have been added to Primary AFTER scn 3162298 they will also have to be restored to the standby host (see Note 1531031.1 Steps to perform for Rolling forward a standby database using RMAN incremental backup when datafile is added to primary) and cataloged as shown above before doing the switch.   

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"

Note:

a) At this point, you can compare the query output from step 9 for any discrepancy (other than newly added datafiles) to ensure we have all the datafiles added in standby.

b) run the queries from step 2 again to confirm that the incremental apply has moved the datafiles forward. The SCN should now be bigger than its initial values.

13) Configure the STANDBY database to use flashback (optional)

If the STANDBY database needs to be configured for FLASHBACK run the following commands:

SQL> ALTER DATABASE FLASHBACK OFF;

SQL> ALTER DATABASE FLASHBACK ON;

NOTE:  This command may return the following:

ORA-38788 More standby database recovery is needed

Depending on situation, this is expected.  Proceed with the remaining steps.

14) On STANDBY database, clear all standby redo log groups:

SQL> select GROUP# from v$logfile where TYPE='STANDBY' group by GROUP#;

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;