Offloading Backup to Standby in Data Guard

As Oracle Data Guard came up with many advantages, One of its benefits is we can offload backup to Physical Standby Database.

Using the RMAN Recovery Catalog in a Data Guard Configuration

 

We need to user Recover Catalog to offload backup to the standby database.

We will offload backup to the physical standby database in 3 stages and then we will test that backup by restoring it to another server.

  1. Creating Recovery Catalog
  2. Registering database in the recovery catalog.
  3. Taking the backup using Physical Standby.
  4. Restoring a backup to test.

Creating Recovery Catalog : 

Step 1: Checking details of the database to be used for recovery catalog.

SQL> select name,open_mode from v$database;

NAME       OPEN_MODE
--------- --------------------
DEMO      READ WRITE

Step 2: Create tablespace in recovery catalog :

SQL> create tablespace ctl datafile '/u01/oracle/oradata/demo/ctl.dbf' size 200m;

Tablespace created.

Step 3: Create the user to be used as recovery catalog owner :

SQL> create user ctl_db identified by ctl_db default tablespace ctl quota unlimited on ctl;

User created.

Step 4: grant recovery_catalog_owner grant to a user.

SQL> grant recovery_catalog_owner to ctl_db;

Grant succeeded.

Step 5: Add TNS entry of primary database and standby database in the server where recovery catalog database resides.

testdb =
  (DESCRIPTION =
    #(ADDRESS = (PROTOCOL = TCP)(HOST = localhost)(PORT = 1522))
    (ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.1.16)(PORT = 1521))
    (CONNECT_DATA =
      (SERVER = DEDICATED)
      (SERVICE_NAME = testdb)
    )
  )
std_testdb =
  (DESCRIPTION =
    #(ADDRESS = (PROTOCOL = TCP)(HOST = localhost)(PORT = 1522))
    (ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.1.10)(PORT = 1521))
    (CONNECT_DATA =
      (SERVER = DEDICATED)
      (SERVICE_NAME = testdb)
    )
  )

Step 6: Connect RMAN with target and catalog clause. target clause contains the primary database and catalog clause contains the catalog database 

[oracle@localhost admin]$ rman target sys/oracle@testdb catalog ctl_db/ctl_db@demo

Recovery Manager: Release 11.2.0.4.0 - Production on Wed May 23 23:39:58 2018

Copyright (c) 1982, 2011, Oracle and/or its affiliates.  All rights reserved.

connected to target database: TESTDB (DBID=2756866105)
connected to recovery catalog database

Step 7: Apply to create catalog command of RMAN to create recovery catalog.

RMAN> create catalog;

recovery catalog created

In this stage recovery catalog is created, now we need to register the primary database.

Step 8: Register the primary database in the recovery catalog

RMAN> register database;

database registered in recovery catalog
starting full resync of recovery catalog
full resync complete

Step 9: We can use report schema recovery catalog command to check the physical structure of the database.

RMAN> report schema;

Report of database schema for database with db_unique_name TESTDB

List of Permanent Datafiles
===========================
File Size(MB) Tablespace           RB segs Datafile Name
---- -------- -------------------- ------- ------------------------
1    740      SYSTEM               YES     /u01/oracle/oradata/testdb/system01.dbf
2    540      SYSAUX               NO      /u01/oracle/oradata/testdb/sysaux01.dbf
3    50       UNDOTBS1             YES     /u01/oracle/oradata/testdb/undotbs01.dbf
4    5        USERS                NO      /u01/oracle/oradata/testdb/users01.dbf

List of Temporary Files
=======================
File Size(MB) Tablespace           Maxsize(MB) Tempfile Name
---- -------- -------------------- ----------- --------------------
1    20       TEMP                 32767       /u01/oracle/oradata/testdb/temp01.dbf

Step 10: List db_unique_name of database.

RMAN> list db_unique_name of database;


List of Databases
DB Key  DB Name  DB ID            Database Role    Db_unique_name
------- ------- ----------------- ---------------  ------------------
1       TESTDB   2756866105       PRIMARY          TESTDB

Step 11: Configure the standby database to the recovery catalog.

RMAN> configure db_unique_name 'std_testdb' connect identifier 'std_testdb';

new RMAN configuration parameters:
CONFIGURE DB_UNIQUE_NAME 'std_testdb' CONNECT IDENTIFIER  'std_testdb';
new RMAN configuration parameters are successfully stored
starting full resync of recovery catalog
full resync complete

Step 12: Now again check the database using list db_unique_name of database command.

RMAN> list db_unique_name of database;

List of Databases
DB Key  DB Name  DB ID            Database Role    Db_unique_name
------- ------- ----------------- ---------------  ------------------
1       TESTDB   2756866105       PRIMARY          TESTDB              
1       TESTDB   2756866105       STANDBY          STD_TESTDB          

RMAN>

Our recovery catalog is ready in this stage. Now we will configure parameters and will take backup

Step 1: Configure controlfile autobackup on.

RMAN> configure controlfile autobackup on;

new RMAN configuration parameters:
CONFIGURE CONTROLFILE AUTOBACKUP ON;
new RMAN configuration parameters are successfully stored
starting full resync of recovery catalog
full resync complete

Step 2: Now connect to the physical standby database as the target and connect to the catalog and take incremental level 0 or full backup

[oracle@localhost admin]$ rman target / catalog ctl_db/ctl_db@catalog

Recovery Manager: Release 11.2.0.4.0 - Production on Thu May 24 00:44:29 2018

Copyright (c) 1982, 2011, Oracle and/or its affiliates.  All rights reserved.

connected to target database: TESTDB (DBID=2756866105)
connected to recovery catalog database

RMAN> list db_unique_name of database;


List of Databases
DB Key  DB Name  DB ID            Database Role    Db_unique_name
------- ------- ----------------- ---------------  ------------------
1       TESTDB   2756866105       PRIMARY          TESTDB              
1       TESTDB   2756866105       STANDBY          STD_TESTDB          

RMAN> backup incremental level 0 database;

Starting backup at 24-MAY-18
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=92 device type=DISK
channel ORA_DISK_1: starting incremental level 0 datafile backup set
channel ORA_DISK_1: specifying datafile(s) in backup set
input datafile file number=00001 name=/u01/oracle/oradata/testdb/system01.dbf
input datafile file number=00002 name=/u01/oracle/oradata/testdb/sysaux01.dbf
input datafile file number=00003 name=/u01/oracle/oradata/testdb/undotbs01.dbf
input datafile file number=00004 name=/u01/oracle/oradata/testdb/users01.dbf
channel ORA_DISK_1: starting piece 1 at 24-MAY-18
channel ORA_DISK_1: finished piece 1 at 24-MAY-18
piece handle=/u01/oracle/fast_recovery_area/STD_TESTDB/backupset/2018_05_24/o1_mf_nnnd0_TAG20180524T004516_fjchg6bx_.bkp tag=TAG20180524T004516 comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:01:05
Finished backup at 24-MAY-18

Starting Control File and SPFILE Autobackup at 24-MAY-18
piece handle=/u01/oracle/fast_recovery_area/STD_TESTDB/autobackup/2018_05_24/o1_mf_s_976315842_fjchjbqx_.bkp comment=NONE
Finished Control File and SPFILE Autobackup at 24-MAY-18

RMAN>

Now we have successfully taken backup from standby database lets transfer it test server and test it.

Step 1: Transfer backup using rsync

[oracle@localhost fast_recovery_area]$ rsync -azvrh --progress STD_TESTDB/* 192.168.1.15:/u01/oracle/fast_recovery_area/STD_TESTDB/
oracle@192.168.1.15's password: 
sending incremental file list
autobackup/
autobackup/2018_05_24/
autobackup/2018_05_24/o1_mf_s_976315842_fjchjbqx_.bkp
      10.13M 100%   22.03MB/s    0:00:00 (xfer#1, to-check=2/7)
backupset/
backupset/2018_05_24/
backupset/2018_05_24/o1_mf_nnnd0_TAG20180524T004516_fjchg6bx_.bkp
       1.11G 100%    5.40MB/s    0:03:16 (xfer#2, to-check=0/7)
onlinelog/

sent 265.03M bytes  received 70 bytes  1.32M bytes/sec
total size is 1.12G  speedup is 4.23
[oracle@localhost fast_recovery_area]$

Step 2 : Create necessary directories on the test server so we can restore primary database backup here.

[oracle@localhost oracle]$ mkdir -p /u01/oracle/admin/testdb/adump
[oracle@localhost oracle]$ mkdir -p /u01/arc/testdb/standbylog
[oracle@localhost oracle]$ mkdir -p /u01/arc/testdb/stdby
[oracle@localhost oracle]$ mkdir -p /u01/oracle/fast_recovery_area/testdb
[oracle@localhost oracle]$ mkdir -p /u01/oracle/fast_recovery_area/STD_TESTDB

Step 3 : Check backup is arrived or not

[oracle@localhost oracle]$ cd /u01/oracle/fast_recovery_area/STD_TESTDB/
[oracle@localhost STD_TESTDB]$ ll
total 12
drwxr-x--- 3 oracle oinstall 4096 May 24 00:46 autobackup
drwxr-x--- 3 oracle oinstall 4096 May 24 00:45 backupset
drwxr-x--- 2 oracle oinstall 4096 Apr 18 22:54 onlinelog

Step 4 : Connect to RMAN and follow the restore process.

Start database in the nomount stage :

[oracle@localhost STD_TESTDB]$ export ORACLE_SID=testdb
[oracle@localhost STD_TESTDB]$ rman target /

Recovery Manager: Release 11.2.0.4.0 - Production on Thu May 24 00:51:35 2018

Copyright (c) 1982, 2011, Oracle and/or its affiliates.  All rights reserved.

connected to target database (not started)

RMAN> startup nomount

Oracle instance started

Total System Global Area     417546240 bytes

Fixed Size                     2253824 bytes
Variable Size                331353088 bytes
Database Buffers              79691776 bytes
Redo Buffers                   4247552 bytes

Step 5 : Restore spfile 

RMAN> restore spfile to pfile '/u01/oracle/product/11.2.0/db_1/dbs/inittestdb.ora' from autobackup;

Starting restore at 24-MAY-18
using channel ORA_DISK_1

recovery area destination: /u01/oracle/fast_recovery_area
database name (or database unique name) used for search: TESTDB
channel ORA_DISK_1: AUTOBACKUP /u01/oracle/fast_recovery_area/TESTDB/autobackup/2018_03_26/o1_mf_s_971803194_fckqm2mh_.bkp found in the recovery area
AUTOBACKUP search with format "%F" not attempted because DBID was not set
channel ORA_DISK_1: restoring spfile from AUTOBACKUP /u01/oracle/fast_recovery_area/TESTDB/autobackup/2018_03_26/o1_mf_s_971803194_fckqm2mh_.bkp
channel ORA_DISK_1: SPFILE restore from AUTOBACKUP complete
Finished restore at 24-MAY-18

Step 6 : Restore controlfile

RMAN> restore controlfile from autobackup;

Starting restore at 24-MAY-18
using channel ORA_DISK_1

recovery area destination: /u01/oracle/fast_recovery_area
database name (or database unique name) used for search: TESTDB
channel ORA_DISK_1: AUTOBACKUP /u01/oracle/fast_recovery_area/TESTDB/autobackup/2018_03_26/o1_mf_s_971803194_fckqm2mh_.bkp found in the recovery area
AUTOBACKUP search with format "%F" not attempted because DBID was not set
channel ORA_DISK_1: restoring control file from AUTOBACKUP /u01/oracle/fast_recovery_area/TESTDB/autobackup/2018_03_26/o1_mf_s_971803194_fckqm2mh_.bkp
channel ORA_DISK_1: control file restore from AUTOBACKUP complete
output file name=/u01/oracle/oradata/testdb/control01.ctl
output file name=/u01/oracle/oradata/testdb/control02.ctl
Finished restore at 24-MAY-18

RMAN>

Step 7 : Mount database

RMAN> alter database mount;

database mounted
released channel: ORA_DISK_1

RMAN>

Step 8 : Now let us first check in sql session mounted database role

SQL> select name,open_mode,database_role from v$database;

NAME       OPEN_MODE           DATABASE_ROLE
--------- -------------------- ----------------
TESTDB     MOUNTED              PRIMARY

 

We can see here database role is primary . So a backup taken from physical standby in data guard broker works fine to restore as a primary database.
Now, we can go further for the restoration process.

Step 9 : Restore database

RMAN> restore database;

Starting restore at 24-MAY-18
Starting implicit crosscheck backup at 24-MAY-18
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=19 device type=DISK
Crosschecked 1 objects
Finished implicit crosscheck backup at 24-MAY-18

Starting implicit crosscheck copy at 24-MAY-18
using channel ORA_DISK_1
Finished implicit crosscheck copy at 24-MAY-18

searching for all files in the recovery area
cataloging files...
cataloging done

List of Cataloged Files
=======================
File Name: /u01/oracle/fast_recovery_area/TESTDB/autobackup/2018_03_26/o1_mf_s_971803194_fckqm2mh_.bkp

using channel ORA_DISK_1

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 00001 to /u01/oracle/oradata/testdb/system01.dbf
channel ORA_DISK_1: restoring datafile 00002 to /u01/oracle/oradata/testdb/sysaux01.dbf
channel ORA_DISK_1: restoring datafile 00003 to /u01/oracle/oradata/testdb/undotbs01.dbf
channel ORA_DISK_1: restoring datafile 00004 to /u01/oracle/oradata/testdb/users01.dbf
channel ORA_DISK_1: reading from backup piece /u01/oracle/fast_recovery_area/TESTDB/backupset/2018_03_26/o1_mf_nnndf_TAG20180326T171817_fckqj1xr_.bkp
channel ORA_DISK_1: piece handle=/u01/oracle/fast_recovery_area/TESTDB/backupset/2018_03_26/o1_mf_nnndf_TAG20180326T171817_fckqj1xr_.bkp tag=TAG20180326T171817
channel ORA_DISK_1: restored backup piece 1
channel ORA_DISK_1: restore complete, elapsed time: 00:00:55
Finished restore at 24-MAY-18

RMAN>

Step 10 : Recover database

RMAN> recover database;

Starting recover at 24-MAY-18
using channel ORA_DISK_1

starting media recovery
media recovery complete, elapsed time: 00:00:00

Finished recover at 24-MAY-18

RMAN>

Stay tuned for More articles on Oracle DataGuard

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About The Author

I am 11g OCP and OCE(RAC and GRID Infrastructure). Currently working as Oracle Database Administrator at _VOIS and Blogger (Freelancer) at Oracle-help . Previously I worked with Acute Informatics pvt ltd. and Mobile Tornado where I handled Banking Data Migration , created DR using log shipping , Golden Gate and Data Guard. I have experience of handling planned and unplanned DB role switchover and failovers and monitoring and troubleshooting Database Performance. Key skills : RMAN , GG , DG , RAC , Virtualization in OVMM.I have experience in Banking and Telecom domain. Reach me at : https://www.linkedin.com/in/jagruti-jasleniya

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