Rman Recovery Scenarios

Rman recovery scenarios require that the database is in archive log mode, and that
backups of datafiles, control files and archived
redolog files are made using Rman. Incremental Rman backups may be used also.
Rman can be used with the repository installed on the archivelog, or with a
recovery catalog that may be installed in the same or
other database.
Configuration and operation recommendations:
Set the parameter controlfile autobackup to ON to have with each backup a
controlfile backup also:
configure controlfile autobackup on;
Set the parameter retention policy to the recovery window you want to have,
ie redundancy 2 will keep the last two backups
available, after executing delete obsolete commands:
configure retention policy to redundancy 2;
Execute your full backups with the option 'plus archivelogs' to include your
archivelogs with every backup:
backup database plus archivelog;
Perform daily maintenance routines to maintain on your backup directory
the number of backups you need only:
crosscheck backup;
crosscheck archivelog all;
delete noprompt obsolete backup;

To work with Rman and a database based catalog follow these steps:-
1. sqlplus /
2. create tablespace repcat;
3. create user rcuser identified by rcuser default tablespace repcat temporary
    tablespace temp;
4. grant connect, resource, recovery_catalog_owner to rcuser
5. exit
6. rman catalog rcuser/rcuser     # connect to rman catalog as the rcuser
7. create catalog                       # create the catalog
8. connect target /

Complete Closed Database Recovery. System tablespace is missing:-
In this case complete recovery is performed, only the system tablespace is missing,
so the database can be opened without reseting
the redologs.
1.rman target /
2.startup mount;
3.restore database;
4.recover database;
5.alter database open;

Complete Open Database Recovery. Non system tablespace is missing, database is up:-
1.rman target /
2.sql 'alter tablespace <tablespace_name> offline immediate';
3.restore datafile 3;
4.recover datafile 3;
5.sql 'alter tablespace <tablespace_name> online';

Complete Open Database Recovery (when the database is initially closed).Non system tablespace is missing:-
A user datafile is reported missing when tryin to startup the database. The datafile
can be turned offline and the database started up. Restore and
recovery are performed using Rman. After recovery is performed the datafile can
be turned online again.

1.sqlplus /nolog
2.connect / as sysdba
3.startup mount
4.alter database datafile '<datafile_name>' offline;
5.alter database open;
6.exit;
7.rman target /
8.restore datafile '<datafile_name>';
9.recover datafile '<datafile_name>';
10.sql 'alter tablespace <tablespace_name> online';

Recovery of a Datafile that has no backups (database is up):
If a non system datafile that was not backed up since the last backup is missing,
recovery can be performed if all archived logs since the creation
of the missing datafile exist. Since the database is up you can check the tablespace
name and put it offline. The option offline immediate is used
to avoid that the update of the datafile header.
Pre requisites: All relevant archived logs.

1.sqlplus '/ as sysdba'
2.alter tablespace <tablespace_name> offline immediate;
3.alter database create datafile '/user/oradata/u01/dbtst/newdata01.dbf;
4.exit
5.rman target /
6.recover tablespace <tablespace_name>;
7.sql 'alter tablespace <tablespace_name> online';

If the create datafile command needs to be executed to place the datafile on a
location different than the original use:
alter database create datafile '/user/oradata/u01/dbtst/newdata01.dbf' as
'/user/oradata/u02/dbtst/newdata01.dbf'


Restore and Recovery of a Datafile to a different location. (Database is up):-
If a non system datafile is missing and its original location not available, restore
can be made to a different location and recovery performed.
Pre requisites: All relevant archived logs, complete cold or hot backup.
1.Use OS commands to restore the missing or corrupted datafile to the new
   location, ie:
   cp -p /user/backup/uman/user01.dbf /user/oradata/u02/dbtst/user01.dbf
2.alter tablespace <tablespace_name> offline immediate;
3.alter tablespace <tablespace_name> rename datafile
   '/user/oradata/u01/dbtst/user01.dbf' to '/user/oradata/u02/dbtst/user01.dbf';
4.rman target /
5.recover tablespace <tablespace_name>;
6.sql 'alter tablespace <tablespace_name> online';

Control File Recovery:-
Always multiplex your controlfiles. If you loose only one controlfile you can
replace it with the one you have in place, and startup the
Database. If both controlfiles are missing, the database will crash.
Pre requisites: A backup of your controlfile and all relevant archived logs. When
using Rman alway set configuration parameter
autobackup of controlfile to ON. You will need the dbid to restore the controlfile,
get it from the name of the backed up controlfile.
It is the number following the 'c-' at the start of the name.
1.rman target /
2.set dbid <dbid#>
3.startup nomount;
4.restore controlfile from autobackup;
5.alter database mount;
6.recover database;
7.alter database open resetlogs;
8.make a new complete backup, as the database is open in a new incarnation and
   previous archived log are not relevant.

Incomplete Recovery, Until Time/Sequence/Cancel:-
Incomplete recovery may be necessaire when the database crash and needs to be
recovered, and in the recovery process you find that
an archived log is missing. In this case recovery can only be made until the
sequence before the one that is missing.
Another scenario for incomplete recovery occurs when an important object was
dropped or incorrect data was committed on it.
In this case recovery needs to be performed until before the object was dropped.
Pre requisites: A full closed or open database backup and archived logs, the time or
sequence that the 'until' recovery needs to be performed.
1.If the database is open, shutdown it to perform full restore.
2.rman target \
3.startup mount;
4.restore database;
5.recover database until sequence 8 thread 1; # you must pass the thread, if a
   single instance will always be 1.
6.alter database open resetlogs;
7.make a new complete backup, as the database is open in a new incarnation and
   previous archived log are not relevant.
 
*Alternatively you may use instead of until sequence, until time, ie: '2004-12-
  28:01:01:10'.