Tuesday, October 19, 2021

RMAN Restore and Recovery Scenarios




Full Database Restore


$ORACLE_HOME/bin/rman target / nocatalog
RMAN> shutdown abort;
RMAN> startup mount;
RMAN> restore database;
RMAN> recover database;
RMAN> alter database open;


 

Tablespace Restore (online)

$rman target / nocatalog
RMAN> sql ‘alter tablespace users offline';
RMAN> restore tablespace users;
RMAN> recover tablespace users;
RMAN> sql ‘alter tablespace users online';


 

Tablespace Restore (offline)

$rman target / nocatalog
RMAN> shutdown abort;
RMAN> startup mount;
RMAN> restore tablespace users;
RMAN> recover tablespace users;
RMAN> alter database open;
database opened


 

Restoring a Specific Datafile

$rman target / nocatalog
RMAN> shutdown abort;
RMAN> startup mount;
RMAN> restore datafile ‘/oradata/DB1/dbf/users01.dbf';
RMAN> recover datafile ‘/oradata/DB1/dbf/users01.dbf';
RMAN> alter database open;
database opened


 

Control File Restoration

Prerequisite: In your rman backup directory determine the latest control file backup.
Default Format: c-nnnnnnnnnn-nnnnnnnn-nn


$rman target / nocatalog
RMAN> shutdown abort;
RMAN> startup nomount;
RMAN> set dbid = 1184749195
RMAN> restore controlfile from ‘/oradata/DB1/rman/c-1184749195-20060626-02′
RMAN> alter database mount;
RMAN> restore database;
RMAN> recover database;
RMAN> alter database open resetlogs;
database opened
Database Point-In-Time-Recovery (PITR)


Also known as time-based incomplete recovery.

$rman target / nocatalog
RMAN> shutdown abort;
RMAN> startup mount;
RMAN> restore database until time “to_date(’09/03/07 13:00:00′, ‘MM/DD/YY HH24:MI:SS’)”;
RMAN> recover database until time “to_date(’09/03/07 13:00:00′, ‘MM/DD/YY HH24:MI:SS’)”;
RMAN> alter database open resetlogs;
database opened


* Make sure you perform a full backup after this operation!

Restore to Another System

Prerequisites
Ideally ensure destination system configured exactly like source.
Same OS version and patch level.
Same drives (C:, D:, S: etc.).
CPU and RAM same or better.
The same version of Oracle is installed on the target system as the source.
Ensure the ORACLE_HOME and ORACLE_SID environment variables are set.
Ensure the listener is running.


Copy RMAN backupset files to the destination system rman directory.

Procedure

Restore SPFILE and Control File

$rman target / nocatalog
RMAN> set dbid 161080442
RMAN> startup nomount;
Creates the file: %ORACLE_HOME%\database\hc_db1.dat
RMAN> restore spfile from ‘R:\rman\C-161080442-20080313-00′;
Creates the file: %ORACLE_HOME%\database\SPFILEDB1.ORA
RMAN> startup force nomount
RMAN> restore controlfile from ‘R:\rman\C-161080442-20080313-00′;
RMAN> shutdown immediate
RMAN> exit



Restore and Recover the Data

$rman target / nocatalog
RMAN> startup mount;
RMAN> restore database;
For a large database this step may take some time.
RMAN> recover database;
If you do not have\need the very last log(s) you can disregard any error messages.
ORA-00310: archived log contains sequence 100; sequence 101 required…
RMAN> alter database open resetlogs;
database opened

Scenario Basis of Recovery

1-  If you lost all data files


SQL> startup mount;
RMAN> restore database;
RMAN> recover database;
SQL> alter database open;

2- If you lost a tablespace


SQL> alter tablespace users offline;
RMAN> restore tablespace users;
RMAN> recover tablespace users;
SQL> alter tablespace users online;

 if you can not offline tablespace;


$ sqlplus “/ as sysdba”
SQL> shutdown abort;
SQL> startup mount;
$ rman target / 
catalog_user/catalog_user_password@catalogdb
RMAN> restore tablespace users;
RMAN> recover tablespace users;
SQL> alter database open;


3- if you lost a datafile


SQL> alter database datafile '/oracle/oradata/users.dbf' offline;
RMAN> restore datafile '/oracle/oradata/users.dbf'
RMAN> recover datafile '/oracle/oradata/users.dbf'
SQL> alter database datafile '/oracle/oradata/users.dbf' online;
 
if you cannot offline datafile;

$ sqlplus “/ as sysdba”
SQL> shutdown abort;
SQL> startup mount;
$ rman target / 
catalog_user/catalog_user_password@catalogdb
RMAN> restore datafile '/oracle/oradata/users.dbf';
RMAN> recover datafile '/oracle/oradata/users.dbf';
SQL> alter database open;
 



4-  if you lost your controlfiles


$ sqlplus “/ as sysdba”
SQL> shutdown abort;
SQL> startup nomount;
$ rman target / 
catalog_user/catalog_user_password@catalogdb
RMAN> set dbid = 3970640872;
RMAN> restore controlfile;
SQL> alter database mount;
SQL> alter database open;

you will receive an error ORA-01589 when you open database
 ORA-01589: must use RESETLOGS or NORESETLOGS option for database open



SQL> shutdown abort;
SQL> startup mount;
$ rman target / 
catalog_user/catalog_user_password@catalogdb
RMAN> recover database;
SQL> alter database open resetlogs;
RMAN> reset database;

if you open database with resetlogs, SCN number will be zero. In this situation
 all previous backups will be invalid. You must full backup.


5- May be a special situation. You need to incomplete recovery


 A. Time-Based incomplete recovery


$ sqlplus "/ as sysdba"
SQL> shutdown abort;
SQL> startup mount;
$ rman target / 
catalog_user/catalog_user_password@catalogdb
RMAN> restore database until time "to_date('06/05/11 12:0:00','DD/MM/YY HH24:MI:SS')";
RMAN> recover database until time "to_date('06/05/11 12:0:00','DD/MM/YY HH24:MI:SS')";
SQL> alter database open resetlogs;
 
 


 B. SCN-Based incomplete recovery


$ sqlplus "/ as sysdba"
SQL> shutdown abort;
SQL> startup mount;
$ rman target / 
catalog_user/catalog_user_password@catalogdb
RMAN> restore database until scn 1000;
RMAN> recover database until scn 1000;
SQL> alter database open resetlogs;


 C. Archive log sequence based incomplete recovery


$ sqlplus "/ as sysdba"
SQL> shutdown abort;
SQL> startup mount;
$ rman target / 
catalog_user/catalog_user_password@catalogdb
RMAN> restore database until sequence 9923;
RMAN> recover database until sequence 9923;
SQL> alter database open resetlogs;



6-  if you need some archive logs in your backup


$ rman target / catalog_user/catalog_user_password@catalogdb
RMAN> restore ARCHIVELOG FROM TIME 'SYSDATE-1' UNTIL TIME 'SYSDATE';
 
OR



RMAN> restore ARCHIVELOG FROM TIME "to_date('07/11/05 00:00:01','MM/DD/YY HH24:MI:SS')
UNTIL TIME 'SYSDATE';
 


7- if your data block is corrupted you will receive an error below.

Error:
 ORA-01578: ORACLE data block corrupted (file # 8, block # 13)
 ORA-01110: data file 8: ‘/oracle/oradata/users.dbf’


for recover data block;


$ rman target / catalog_user/catalog_user_password@catalogdb
RMAN>blockrecover datafile 8 block 13;
 
For Block-Level Media Recovery – Concept & Example (Doc ID 144911.1)

 To recover, we can give a specific backup set;


# recovery from backupset

RMAN> BLOCKRECOVER DATAFILE 8 BLOCK 13 DATAFILE 2 BLOCK 19 FROM BACKUPSET;

# recovery from image copy

RMAN> BLOCKRECOVER DATAFILE 8 BLOCK 13 DATAFILE 2 BLOCK 19
      FROM DATAFILECOPY;

# recovery from backupset which have "FULL" tag


RMAN> BLOCKRECOVER DATAFILE 8 BLOCK 13 DATAFILE 2 BLOCK 199
       FROM TAG = FULL;
During backup or “Validate Backup” command, RMAN finds corrupted blocks and writes to V$DATABASE_BLOCK_CORRUPTION view. When the RMAN recover the corrupt block then automatically updates this view. List of all the corruption of the past, can be viewed over V$BACKUP_CORRUPTION and V$COPY_CORRUPTION views.  If you run the following command,  RMAN will recover all the corrupted blocks in view V$DATABASE_BLOCK_CORRUPTION.



  RMAN>BLOCKRECOVER CORRUPTION LIST RESTORE UNTIL TIME 'SYSDATE-10';

8- if you have a image copy backup and your datafile number 2 has problems then you

can switch datafile number2 to image copy.


RMAN>sql ‘alter database datafile 2 offline’;
RMAN>switch datafile 2 to copy;
RMAN>recover datafile 2;
RMAN>sql ‘alter database datafile 2 online’;

  

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