Database Disaster Recovery using only RMAN Backups

Before we take our case to the RMAN Backups, 2 pre-conditions need to be fulfilled:

1. A Server (the same server or a new one) should be made available in a state where Oracle

Product can be installed; i.e., it should be brought online with a functional Operating System

and necessary Environment Configurations, same as how it was before the crash.

2. Same version of Oracle Product (including any patch sets) needs to be installed with which the RMAN Backup was taken. This is critical for the recovery to be successful.

For the demonstration, the Operating System used Microsoft Windows 2003 and the Oracle

Database Product used 10g R2 (10.2.0.4) Standard Edition.

The following steps would outline the procedures for recovering the Database using only RMAN Backup:

1. Create the Oracle Service

2. Create the relevant folder hierarchy under <ORACLE_BASE> directory

3. Restore the SPFILE from autobackup, and use the SPFILE to start the instance in NOMOUNT state

4. Restore the controlfile from autobackup, and MOUNT the database

5. Restore the Database from RMAN backup files

6. Recover the Database from RMAN backup files, and OPEN the database with RESETLOGS

GETTING STARTED

1. Create the Oracle Service

We need to create an Oracle Service using 'oradim' utility, without passing any PFILE information

C:\>oradim -new -sid DBTEST -intpwd DBTEST

Instance created.

NOTE: 10g onwards, we can directly specify the SPFILE for oracle service creation; thanks to the newly introduced

SPFILE option in oradim utility.

2. Create the relevant folder hierarchy under <ORACLE_BASE> directory

Now, we need to create the relevant directories for Oracle Database, as follows:

a. Create BDUMP, CDUMP, and UDUMP directories under '<ORACLE_ BASE>\admin'

directory,

b. Create <DATABASE_NAME> directory under '<ORACLE_BASE>\oradata' directory; in our

case DBTEST.

3. Restore the SPFILE from autobackup, and use the SPFILE to start the

instance in NOMOUNT state

Here, we need to connect to the Recovery Manager using the ‘rman’ utility, and then start the Recovery process. First we need to set the Database ID (DBID) of the Database. At times, we may or may not know the DBID of the Database. There are 2 ways to find the DBID:

a. If RMAN Backup text logs are maintained, the DBID can be found when the initial connection

is made to the target , or

b. If autobackup is enabled and has the autobackup format set (let’s say the format is '%F'), then

the filename of the autobackup has the DBID in it.

In our case, 'c-1106578690-20100408-00' is the name of the autobackup file; so the DBID should be

'1106578690'.

Next, we need to set the autobackup location, which will help us identify the location of all the RMAN

files.

In our case, the RMAN autobackup and backup files are located at '\\testdb\dbtest\'.

C:\>set oracle_sid=DBTEST

C:\>rman target /

Recovery Manager: Release 10.2.0.1.0 - Production on Thu Apr 8 11:40:10 2010

Copyright (c) 1982, 2005, Oracle. All rights reserved.

connected to target database (not started)

RMAN> set dbid=1106578690;

executing command: SET DBID

RMAN> startup force nomount;

startup failed: ORA-01078: failure in processing system parameters

LRM-00109: could not open parameter file

'C:\ORACLE\PRODUCT\10.2.0\DB_2\DATABASE\INITDBTEST.ORA'

starting Oracle instance without parameter file for retrival of spfile

Oracle instance started

Total System Global Area 159383552 bytes

Fixed Size 1247828 bytes

Variable Size 58721708 bytes

Database Buffers 92274688 bytes

Redo Buffers 7139328 bytes

RMAN> SET CONTROLFILE AUTOBACKUP FORMAT FOR DEVICE TYPE DISK TO

'\\testdb\dbtest\%F';

executing command: SET CONTROLFILE AUTOBACKUP FORMAT

using target database control file instead of recovery catalog

NOTE: It is a good practice to generate the text logs whenever your RMAN backup runs and have the command “show all” run before the backup and “list backup” after the backup completes. This ensures that we have information on the complete set of RMAN configurations and a list of all the backups with their details in the text log.

Next, we need to restore the SPFILE from the autobackup file and then use it to restart the instance in NOMOUNT state. You can approach this in two ways, as demonstrated below:

a. Restoring the SPFILE from the autobackup to a non-default location:

We can restore the SPFILE to a non-default location by using any one of the below 2 methods:

RMAN> restore spfile to 'C:\spdbtest01.ora' from autobackup;

Starting restore at 08-APR-10

allocated channel: ORA_DISK_1

channel ORA_DISK_1: sid=36 devtype=DISK

channel ORA_DISK_1: looking for autobackup on day: 20100408

channel ORA_DISK_1: autobackup found: \\testdb\dbtest\c-1106578690-20100408-

00

channel ORA_DISK_1: SPFILE restore from autobackup complete

Finished restore at 08-APR-10

OR,

RMAN> restore spfile to 'C:\spdbtest02.ora' from "\\testdb\dbtest\c-

1106578690-20100408-00";

Starting restore at 08-APR-10

using channel ORA_DISK_1

channel ORA_DISK_1: autobackup found: \\testdb\dbtest\c-1106578690-20100408-

00

channel ORA_DISK_1: SPFILE restore from autobackup complete

Finished restore at 08-APR-10

Now, we need to restart the instance in NOMOUNT state using the restored parameter file.

RMAN> shutdown immediate

Oracle instance shut down

Remember that we have just restored the SPFILE in a non-default location and hence we would require referring a PFILE that should be referencing the SPFILE, so as to start the instance. For this, we need to create a text file, 'init<SID>.ora', and then mention the path and name of the restored SPFILE in it. In our case, the ‘initDBTEST.ora’ would contain only the following statement:

SPFILE=C:\spdbtest01.ora

Next, we need to start the instance in NOMOUNT state using the newly created PFILE (referencing the SPFILE).

RMAN> startup force pfile=’C:\initDBTEST.ora’ nomount

Oracle instance started

Total System Global Area 377487360 bytes

Fixed Size 1249080 bytes

Variable Size 113246408 bytes

Database Buffers 255852544 bytes

Redo Buffers 7139328 bytes

b. Restoring the SPFILE from the autobackup to the default location:

We can restore the SPFILE to the default location (“<ORACLE_HOME>/database” in Windows) by using any one of the below 2 methods:

RMAN> restore spfile from autobackup;

Starting restore at 08-APR-10

using channel ORA_DISK_1

channel ORA_DISK_1: looking for autobackup on day: 20100408

channel ORA_DISK_1: autobackup found: \\testdb\dbtest\c-1106578690-20100408-

00

channel ORA_DISK_1: SPFILE restore from autobackup complete

Finished restore at 08-APR-10

OR,

RMAN> restore spfile from "\\testdb\dbtest\c-1106578690-20100408-00";

Starting restore at 08-APR-10

using channel ORA_DISK_1

channel ORA_DISK_1: autobackup found: \\testdb\dbtest\c-1106578690-20100408-

00

channel ORA_DISK_1: SPFILE restore from autobackup complete

Finished restore at 08-APR-10

The SPFILE has been restored in the DATABASE directory of the default home location. Oracle will now automatically look for an SPFILE in this location when you try to start the instance

RMAN> shutdown immediate

Oracle instance shut down

Start the instance in NOMOUNT state. Here, we do not need to reference any PFILE or SPFILE, which makes the task a lot simpler.

RMAN> startup force nomount;

Oracle instance started

Total System Global Area 377487360 bytes

Fixed Size 1249080 bytes

Variable Size 113246408 bytes

Database Buffers 255852544 bytes

Redo Buffers 7139328 bytes

Once the database is restarted in NOMOUNT state, we need to restore the controlfiles so as to restore and recover the database using the RMAN Backups.

Again here, we can restore the controlfiles by using any one of the below 2 methods:

RMAN> restore controlfile from autobackup;

Starting restore at 08-APR-10

allocated channel: ORA_DISK_1

channel ORA_DISK_1: sid=156 devtype=DISK

recovery area destination: C:\oracle\flash_recovery_area

database name (or database unique name) used for search: DBTEST

channel ORA_DISK_1: no autobackups found in the recovery area

channel ORA_DISK_1: looking for autobackup on day: 20100408

channel ORA_DISK_1: autobackup found: \\testdb\dbtest\c-1106578690-20100408-00

channel ORA_DISK_1: control file restore from autobackup complete

output filename=C:\ORACLE\ORADATA\DBTEST\CONTROL01.CTL

output filename=C:\ORACLE\ORADATA\DBTEST\CONTROL02.CTL

output filename=C:\ORACLE\ORADATA\DBTEST\CONTROL03.CTL

Finished restore at 08-APR-10

OR,

RMAN> restore controlfile from "\\testdb\dbtest\c-1106578690-20100408-00";

Starting restore at 08-APR-10

using channel ORA_DISK_1

channel ORA_DISK_1: restoring control file

channel ORA_DISK_1: restore complete, elapsed time: 00:00:10

output filename=C:\ORACLE\ORADATA\DBTEST\CONTROL01.CTL

output filename=C:\ORACLE\ORADATA\DBTEST\CONTROL02.CTL

output filename=C:\ORACLE\ORADATA\DBTEST\CONTROL03.CTL

Finished restore at 08-APR-10

5. Restore the Database from RMAN backup files

With the restored controlfiles, we are now in a position to restore the Database. We need to mount the Instance first and then restore the database files from the backup.

RMAN> alter database mount;

database mounted

RMAN> restore database;

Starting restore at 08-APR-10

Starting implicit crosscheck backup at 08-APR-10

allocated channel: ORA_DISK_1

channel ORA_DISK_1: sid=156 devtype=DISK

Crosschecked 4 objects

Finished implicit crosscheck backup at 08-APR-10

Starting implicit crosscheck copy at 08-APR-10

using channel ORA_DISK_1

Finished implicit crosscheck copy at 08-APR-10

searching for all files in the recovery area

cataloging files...

no files cataloged

using channel ORA_DISK_1

channel ORA_DISK_1: starting datafile backupset restore

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

restoring datafile 00001 to C:\ORACLE\ORADATA\DBTEST\SYSTEM01.DBF

restoring datafile 00002 to C:\ORACLE\ORADATA\DBTEST\UNDOTBS01.DBF

restoring datafile 00003 to C:\ORACLE\ORADATA\DBTEST\SYSAUX01.DBF

restoring datafile 00004 to C:\ORACLE\ORADATA\DBTEST\USERS01.DBF

restoring datafile 00005 to C:\ORACLE\ORADATA\DBTEST\TOOLS01.DBF

restoring datafile 00006 to C:\ORACLE\ORADATA\DBTEST\ORT_TBSP01.DBF

restoring datafile 00007 to C:\ORACLE\ORADATA\DBTEST\OR_TBSP01.DBF

restoring datafile 00008 to C:\ORACLE\ORADATA\DBTEST\OR_TBSP02.DBF

restoring datafile 00009 to C:\ORACLE\ORADATA\DBTEST\OR_TBSP03.DBF

restoring datafile 00010 to C:\ORACLE\ORADATA\DBTEST\OR_TBSP04.DBF

restoring datafile 00011 to C:\ORACLE\ORADATA\DBTEST\ORT_INDX01.DBF

restoring datafile 00012 to C:\ORACLE\ORADATA\DBTEST\ORT_INDX02.DBF

restoring datafile 00013 to C:\ORACLE\ORADATA\DBTEST\OR_INDX01.DBF

restoring datafile 00014 to C:\ORACLE\ORADATA\DBTEST\OR_INDX02.DBF

restoring datafile 00015 to C:\ORACLE\ORADATA\DBTEST\OR_INDX03.DBF

restoring datafile 00016 to C:\ORACLE\ORADATA\DBTEST\OR_TEST01.DBF

restoring datafile 00017 to C:\ORACLE\ORADATA\DBTEST\PY_TBSP01.DBF

restoring datafile 00018 to C:\ORACLE\ORADATA\DBTEST\IT_INDX01.DBF

restoring datafile 00019 to C:\ORACLE\ORADATA\DBTEST\IT_TBSP01.DBF

restoring datafile 00020 to C:\ORACLE\ORADATA\DBTEST\PY_TBSP02.DBF

restoring datafile 00021 to C:\ORACLE\ORADATA\DBTEST\PY_INDX01.DBF

channel ORA_DISK_1: reading from backup piece

\\TESTDB\DBTEST\DBTEST_04LAJPNP_1_1_20100408

channel ORA_DISK_1: restored backup piece 1

piece handle=\\TESTDB\DBTEST\DBTEST_04LAJPNP_1_1_20100408

tag=TAG20100408T110945

channel ORA_DISK_1: restore complete, elapsed time: 00:31:38

Finished restore at 08-APR-10

Once restoration of the database is complete, we need to recover the database by applying the archivelogs from the backup.

RMAN> recover database;

Starting recover at 08-APR-10

using channel ORA_DISK_1

starting media recovery

channel ORA_DISK_1: starting archive log restore to default destination

channel ORA_DISK_1: restoring archive log

archive log thread=1 sequence=32

channel ORA_DISK_1: reading from backup piece

\\TESTDB\DBTEST\DBTEST_05LAJR4F_1_1_20100408

channel ORA_DISK_1: restored backup piece 1

piece handle=\\TESTDB\DBTEST\DBTEST_05LAJR4F_1_1_20100408

tag=TAG20100408T113335

channel ORA_DISK_1: restore complete, elapsed time: 00:00:04

archive log

filename=C:\ORACLE\FLASH_RECOVERY_AREA\DBTEST\ARCHIVELOG\2010_04_08\O1_MF_1_32_

5VVJG77X_.ARC thread=1 sequence=32

channel default: deleting archive log(s)

archive log

filename=C:\ORACLE\FLASH_RECOVERY_AREA\DBTEST\ARCHIVELOG\2010_04_08\O1_MF_1_32_

5VVJG77X_.ARC recid=33 stamp=715790711

unable to find archive log

archive log thread=1 sequence=33

RMAN-00571: ===========================================================

RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============

RMAN-00571: ===========================================================

RMAN-03002: failure of recover command at 04/08/2010 14:45:21

RMAN-06054: media recovery requesting unknown log: thread 1 seq 33 lowscn

27801294

Don't panic when you see the above Error Message. You just need to open the database with

RESETLOGS option, as there are no more archivelogs to apply.

RMAN> alter database open resetlogs;

database opened

The Database Disaster Recovery using RMAN is now complete.