RMAN Backup and Recovery

What is RMAN and how does one use it?
Recovery Manager (or RMAN) is an Oracle provided utility for backing-up, restoring and recovering Oracle Databases. RMAN ships with the database server and doesn't require a separate installation. The RMAN executable is located in your ORACLE_HOME/bin directory.
In fact RMAN, is just a Pro*C application that translates commands to a PL/SQL interface. The PL/SQL calls are stallically linked into the Oracle kernel, and does not require the database to be opened (mapped from the ?/rdbms/admin/recover.bsq file).
RMAN can do off-line and on-line database backups. It cannot, however, write directly to tape, but various 3rd-party tools (like Veritas, Omiback, etc) can integrate with RMAN to handle tape library management.
RMAN can be operated from Oracle Enterprise Manager, or from command line. Here are the command line arguments:
Argument Value Description
-----------------------------------------------------------------------------
target quoted-string connect-string for target database
catalog quoted-string connect-string for recovery catalog
nocatalog none if specified, then no recovery catalog
cmdfile quoted-string name of input command file
log quoted-string name of output message log file
trace quoted-string name of output debugging message log file
append none if specified, log is opened in append mode
debug optional-args activate debugging
msgno none show RMAN-nnnn prefix for all messages
send quoted-string send a command to the media manager
pipe string building block for pipe names
timeout integer number of seconds to wait for pipe input
-----------------------------------------------------------------------------
Here is an example:
[oracle@localhost oracle]$ rman
Recovery Manager: Release 10.1.0.2.0 - Production
Copyright (c) 1995, 2004, Oracle. All rights reserved.

RMAN> connect target;

connected to target database: ORCL (DBID=1058957020)

RMAN> backup database;
...

How does one backup and restore a database using RMAN?
The biggest advantage of RMAN is that it only backup used space in the database. RMAN doesn't put tablespaces in backup mode, saving on redo generation overhead. RMAN will re-read database blocks until it gets a consistent image of it. Look at this simple backup example.
rman target sys/*** nocatalog
run {
allocate channel t1 type disk;
backup
format '/app/oracle/backup/%d_t%t_s%s_p%p'
(database);
release channel t1;
}
Example RMAN restore:
rman target sys/*** nocatalog
run {
allocate channel t1 type disk;
# set until time 'Aug 07 2000 :51';
restore tablespace users;
recover tablespace users;
release channel t1;
}
The examples above are extremely simplistic and only useful for illustrating basic concepts. By default Oracle uses the database controlfiles to store information about backups. Normally one would rather setup a RMAN catalog database to store RMAN metadata in. Read the Oracle Backup and Recovery Guide before implementing any RMAN backups.
Note: RMAN cannot write image copies directly to tape. One needs to use a third-party media manager that integrates with RMAN to backup directly to tape. Alternatively one can backup to disk and then manually copy the backups to tape.

How does one backup and restore archived log files?
One can backup archived log files using RMAN or any operating system backup utility. Remember to delete files after backing them up to prevent the archive log directory from filling up. If the archive log directory becomes full, your database will hang! Look at this simple RMAN backup scripts:
RMAN> run {
2> allocate channel dev1 type disk;
3> backup
4> format '/app/oracle/archback/log_%t_%sp%p'
5> (archivelog all delete input);
6> release channel dev1;
7> }
The "delete input" clause will delete the archived logs as they as backed-up.
List all archivelog backups for the past 24 hours:
RMAN> LIST BACKUP OF ARCHIVELOG FROM TIME 'sysdate-1';
Here is a restore example:
RMAN> run {
2> allocate channel dev1 type disk;
3> restore (archivelog low logseq 78311 high logseq 78340 thread 1 all);
4> release channel dev1;
5> }

How does one create a RMAN recovery catalog?
Start by creating a database schema (usually called rman). Assign an appropriate tablespace to it and grant it the recovery_catalog_owner role. Look at this example:
sqlplus sys
SQL> create user rman identified by rman;
SQL> alter user rman default tablespace tools temporary tablespace temp;
SQL> alter user rman quota unlimited on tools;
SQL> grant connect, resource, recovery_catalog_owner to rman;
SQL> exit;
Next, log in to rman and create the catalog schema. Prior to Oracle 8i this was done by running the catrman.sql script.
rman catalog rman/rman
RMAN> create catalog tablespace tools;
RMAN> exit;
You can now continue by registering your databases in the catalog. Look at this example:
rman catalog rman/rman target backdba/backdba
RMAN> register database;
One can also use the "upgrade catalog;" command to upgrade to a new RMAN release, or the "drop catalog;" command to remove an RMAN catalog. These commands need to be entered twice to confirm the operation.

How does one integrate RMAN with third-party Media Managers?
The following Media Management Software Vendors have integrated their media management software with RMAN (Oracle Recovery Manager):
 Veritas NetBackup - http://www.veritas.com/
 EMC Data Manager (EDM) - http://www.emc.com/
 HP OMNIBack/ DataProtector - http://www.hp.com/
 IBM's Tivoli Storage Manager (formerly ADSM) - http://www.tivoli.com/storage/
 EMC Networker - http://www.emc.com/
 BrightStor ARCserve Backup - http://www.ca.com/us/data-loss-prevention.aspx
 Sterling Software's SAMS:Alexandria (formerly from Spectralogic) - http://www.sterling.com/sams/
 SUN's Solstice Backup - http://www.sun.com/software/whitepapers/backup-n-storage/
 CommVault Galaxy - http://www.commvault.com/
 etc...
The above Media Management Vendors will provide first line technical support (and installation guides) for their respective products.
A complete list of supported Media Management Vendors can be found at:http://www.oracle.com/technology/deploy/availability/htdocs/bsp.htm
When allocating channels one can specify Media Management spesific parameters. Here are some examples:
Netbackup on Solaris:
allocate channel t1 type 'SBT_TAPE' PARMS='SBT_LIBRARY=/usr/openv/netbackup/bin/libobk.so.1';
Netbackup on Windows:
allocate channel t1 type 'SBT_TAPE' send "NB_ORA_CLIENT=client_machine_name";
Omniback/ DataProtector on HP-UX:
allocate channel t1 type 'SBT_TAPE' PARMS='SBT_LIBRARY= /opt/omni/lib/libob2oracle8_64bit.sl';
or:
allocate channel 'dev_1' type 'sbt_tape' parms 'ENV=OB2BARTYPE=Oracle8,OB2APPNAME=orcl,OB2BARLIST=machinename_orcl_archlogs)';

How does one clone/duplicate a database with RMAN?
The first step to clone or duplicate a database with RMAN is to create a new INIT.ORA and password file (use the orapwd utility) on the machine you need to clone the database to. Review all parameters and make the required changed. For example, set the DB_NAME parameter to the new database's name.
Secondly, you need to change your environment variables, and do a STARTUP NOMOUNT from sqlplus. This database is referred to as the AUXILIARY in the script below.
Lastly, write a RMAN script like this to do the cloning, and call it with "rman cmdfile dupdb.rcv":
connect target sys/secure@origdb
connect catalog rman/rman@catdb
connect auxiliary /

run {
set newname for datafile 1 to '/ORADATA/u01/system01.dbf';
set newname for datafile 2 to '/ORADATA/u02/undotbs01.dbf';
set newname for datafile 3 to '/ORADATA/u03/users01.dbf';
set newname for datafile 4 to '/ORADATA/u03/indx01.dbf';
set newname for datafile 5 to '/ORADATA/u02/example01.dbf';

allocate auxiliary channel dupdb1 type disk;
set until sequence 2 thread 1;

duplicate target database to dupdb
logfile
GROUP 1 ('/ORADATA/u02/redo01.log') SIZE 200k REUSE,
GROUP 2 ('/ORADATA/u03/redo02.log') SIZE 200k REUSE;
}
The above script will connect to the "target" (database that will be cloned), the recovery catalog (to get backup info), and the auxiliary database (new duplicate DB). Previous backups will be restored and the database recovered to the "set until time" specified in the script.
Notes: the "set newname" commands are only required if your datafile names will different from the target database.
The newly cloned DB will have its own unique DBID.

Can one restore RMAN backups without a CONTROLFILE and RECOVERY CATALOG?
Details of RMAN backups are stored in the database control files and optionally a Recovery Catalog. If both these are gone, RMAN cannot restore the database. In such a situation one must extract a control file (or other files) from the backup pieces written out when the last backup was taken. Let's look at an example:
Let's take a backup (partial in our case for ilustrative purposes):
$ rman target / nocatalog
Recovery Manager: Release 10.1.0.2.0 - 64bit Production
Copyright (c) 1995, 2004, Oracle. All rights reserved.

connected to target database: ORCL (DBID=1046662649)
using target database controlfile instead of recovery catalog

RMAN> backup datafile 1;

Starting backup at 20-AUG-04
allocated channel: ORA_DISK_1
channel ORA_DISK_1: sid=146 devtype=DISK
channel ORA_DISK_1: starting full datafile backupset
channel ORA_DISK_1: specifying datafile(s) in backupset
input datafile fno=00001 name=/oradata/orcl/system01.dbf
channel ORA_DISK_1: starting piece 1 at 20-AUG-04
channel ORA_DISK_1: finished piece 1 at 20-AUG-04
piece handle=
/flash_recovery_area/ORCL/backupset/2004_08_20/o1_mf_nnndf_TAG20040820T153256_0lczd9tf_.bkp comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:00:45
channel ORA_DISK_1: starting full datafile backupset
channel ORA_DISK_1: specifying datafile(s) in backupset
including current controlfile in backupset
including current SPFILE in backupset
channel ORA_DISK_1: starting piece 1 at 20-AUG-04
channel ORA_DISK_1: finished piece 1 at 20-AUG-04
piece handle=
/flash_recovery_area/ORCL/backupset/2004_08_20/o1_mf_ncsnf_TAG20040820T153256_0lczfrx8_.bkp comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:00:04
Finished backup at 20-AUG-04[/code]
Now, let's destroy one of the control files:
SQL> show parameters CONTROL_FILES
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
control_files string /oradata/orcl/control01.ctl,
/oradata/orcl/control02.ctl,
/oradata/orcl/control03.ctl
SQL> shutdown abort;
ORACLE instance shut down.
SQL> ! mv /oradata/orcl/control01.ctl /tmp/control01.ctl
Now, let's see if we can restore it. First we need to start the database in NOMOUNT mode:
SQL> startup NOMOUNT
ORACLE instance started.

Total System Global Area 289406976 bytes
Fixed Size 1301536 bytes
Variable Size 262677472 bytes
Database Buffers 25165824 bytes
Redo Buffers 262144 bytes
Now, from SQL*Plus, run the following PL/SQL block to restore the file:
DECLARE
v_devtype VARCHAR2(100);
v_done BOOLEAN;
v_maxPieces NUMBER;

TYPE t_pieceName IS TABLE OF varchar2(255) INDEX BY binary_integer;
v_pieceName t_pieceName;
BEGIN
-- Define the backup pieces... (names from the RMAN Log file)
v_pieceName(1) :=
'/flash_recovery_area/ORCL/backupset/2004_08_20/o1_mf_ncsnf_TAG20040820T153256_0lczfrx8_.bkp';
v_pieceName(2) :=
'/flash_recovery_area/ORCL/backupset/2004_08_20/o1_mf_nnndf_TAG20040820T153256_0lczd9tf_.bkp';
v_maxPieces := 2;

-- Allocate a channel... (Use type=>null for DISK, type=>'sbt_tape' for TAPE)
v_devtype := DBMS_BACKUP_RESTORE.deviceAllocate(type=>NULL, ident=>'d1');

-- Restore the first Control File...
DBMS_BACKUP_RESTORE.restoreSetDataFile;

-- CFNAME mist be the exact path and filename of a controlfile taht was backed-up
DBMS_BACKUP_RESTORE.restoreControlFileTo(cfname=>'/app/oracle/oradata/orcl/control01.ctl');

dbms_output.put_line('Start restoring '||v_maxPieces||' pieces.');
FOR i IN 1..v_maxPieces LOOP
dbms_output.put_line('Restoring from piece '||v_pieceName(i));
DBMS_BACKUP_RESTORE.restoreBackupPiece(handle=>v_pieceName(i), done=>v_done, params=>null);
exit when v_done;
END LOOP;

-- Deallocate the channel...
DBMS_BACKUP_RESTORE.deviceDeAllocate('d1');
EXCEPTION
WHEN OTHERS THEN
DBMS_BACKUP_RESTORE.deviceDeAllocate;
RAISE;
END;
/
Let's see if the controlfile was restored:
SQL> ! ls -l /oradata/orcl/control01.ctl
-rw-r----- 1 oracle dba 3096576 Aug 20 16:45 /oradata/orcl/control01.ctl[/code]
We should now be able to MOUNT the database and continue recovery...
SQL> ! cp /oradata/orcl/control01.ctl /oradata/orcl/control02.ctl

SQL> ! cp /oradata/orcl/control01.ctl /oradata/orcl/control03.ctl

SQL> alter database mount;

SQL> recover database using backup controlfile;
ORA-00279: change 7917452 generated at 08/20/2004 16:40:59 needed for thread 1
ORA-00289: suggestion :
/flash_recovery_area/ORCL/archivelog/2004_08_20/o1_mf_1_671_%u_.arc
ORA-00280: change 7917452 for thread 1 is in sequence #671

Specify log: {=suggested | filename | AUTO | CANCEL}
/oradata/orcl/redo02.log
Log applied.
Media recovery complete.

Database altered.

SQL> alter database open resetlogs;

Database altered.