Some of the interesting notes on RMAN

1.1. Where should the catalog be created?

The recovery catalog to be used by rman should be created in a seperate database other than the target database. The reason been that the target database will be shutdown while datafiles are restored.

1.2. How do I create a catalog for rman?

First create the user rman.

CREATE USER rman IDENTIFIED BY rman
TEMPORARY TABLESPACE temp
DEFAULT TABLESPACE tools
QUOTA UNLIMITED ON tools;

GRANT connect, resource, recovery_catalog_owner TO rman;
exit

Then create the recovery catalog:-

rman catalog=rman/rman
create catalog tablespace tools;
exit

Then register the database

oracle@debian:~$ rman target=/ catalog=rman/rman@newdb

Recovery Manager: Release 10.1.0.2.0 – Production

Copyright (c) 1995, 2004, Oracle. All rights reserved.

connected to target database: TEST (DBID=1843143191)
connected to recovery catalog database

RMAN> register database;

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

Note
If you try rman catalog=rman/rman and try to register the database it will not work.

Note
We have 2 Databases here 1 is newdb which is solely for catalog and the other is TEST which is our database on which we want to perform all rman operations.

1.3. How many times does oracle ask before dropping a catalog?

The default is two times one for the actual command, the other for confirmation.

1.4. How to view the current defaults for the database.

rman> show all;

RMAN> show all
2> ;

RMAN configuration parameters are:
CONFIGURE RETENTION POLICY TO RECOVERY WINDOW OF 3 DAYS;
CONFIGURE BACKUP OPTIMIZATION OFF; # default
CONFIGURE DEFAULT DEVICE TYPE TO DISK; # default
CONFIGURE CONTROLFILE AUTOBACKUP OFF; # default
CONFIGURE CONTROLFILE AUTOBACKUP FORMAT FOR DEVICE TYPE DISK TO ‘%F’; # default
CONFIGURE DEVICE TYPE DISK PARALLELISM 1 BACKUP TYPE TO BACKUPSET; # default
CONFIGURE DATAFILE BACKUP COPIES FOR DEVICE TYPE DISK TO 1; # default
CONFIGURE ARCHIVELOG BACKUP COPIES FOR DEVICE TYPE DISK TO 1; # default
CONFIGURE MAXSETSIZE TO UNLIMITED; # default
CONFIGURE ARCHIVELOG DELETION POLICY TO NONE; # default
CONFIGURE SNAPSHOT CONTROLFILE NAME TO ‘/u02/app/oracle/product/10.1.0/db_1/dbs/snapcf_test.f’; # default

1.5. Backup the database.

RMAN> run{
configure retention policy to recovery window of 2 days;
backup database plus archivelog;
delete noprompt obsolete;
}
tarting backup at 04-JUL-05
current log archived
allocated channel: ORA_DISK_1
channel ORA_DISK_1: sid=256 devtype=DISK
channel ORA_DISK_1: starting archive log backupset
……………

1.6. How to resolve the ora-19804 error

Basically this error is because of flash recovery area been full. One way to solve is to increase the space available for flashback database.

sql>ALTER SYSTEM SET DB_RECOVERY_FILE_DEST_SIZE=5G; –It can be set to K,M or G.
rman>backup database;
……………….
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 04-JUL-05
channel ORA_DISK_1: finished piece 1 at 04-JUL-05
piece handle=/u02/app/oracle/flash_recovery_area/TEST/backupset/2005_07_04/o1_mf_ncsnf_TAG20050704T205840_1dmy15cr_.bkp comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:00:03
Finished backup at 04-JUL-05

Oracle Flashback

After taking a back up resync the database.

Restoring the whole database.

run {
shutdown immediate;
startup mount;
restore database;
recover database;
alter database open;
}

1.7. What are the various reports available with RMAN

rman>list backup; rman> list archive;

1.8. What does backup incremental level=0 database do?

Backup database level=0 is a full backup of the database. rman>>backup incremental level=0 database;

You can also use backup full database; which means the same thing as level=0;

1.9. What is the difference between DELETE INPUT and DELETE ALL command in backup?

Generally speaking LOG_ARCHIVE_DEST_n points to two disk drive locations where we archive the files, when a command is issued through rman to backup archivelogs it uses one of the location to backup the data. When we specify delete input the location which was backedup will get deleted, if we specify delete all all log_archive_dest_n will get deleted.

DELETE all applies only to archived logs. delete expired archivelog all;

Chapter 2. Recovery

Recovery involves placing the datafiles in the appropriate state for the type of recovery you are performing. If recovering all datafiles, then mount the database, if recovering a single tablespace or datafile then you can keep the database open and take the tablespace or datafile offline. Perform the required recovery and put them back online.

Put the commands in a rman script .rcv file such as myrman.rcv

run
{
# shutdown immediate; # use abort if this fails
startup mount;
#SET UNTIL TIME ‘Nov 15 2001 09:00:00′;
# SET UNTIL SCN 1000; # alternatively, you can specify SCN
SET UNTIL SEQUENCE 9923; # alternatively, you can specify log sequence number
restore database;
recover database;
alter database open;
}

Run the myrman.rcv file as :- rman target / @myrman.rcv

After successful restore & recovery immediately backup your database, because the database is in a new incarnation.

ALTER DATABASE open resetlogs; –command creates a new incarnation of the database — database with a new stream of sequence numbers starting with sequence 1.

Before running RESETLOGS it is a good practice to open the database in read only mode and examining the data contents.

2.1. Simulating media failure.

2.1.1. How to simulate media failure and recover a tablespace in the database ?
2.1.2. What is the difference between alter database recover and sql*plus recover command?

2.1.1. How to simulate media failure and recover a tablespace in the database ?

Firstly create the table in the required tablespace.

CREATE TABLE mytest ( id number(10));

Then insert into the table mytest values(100); execute the insert statement a couple of times but do not commit the results.

Take the tablespace offline, this is possible only if the database is in archivelog mode.

now commit the transaction. by issuing commit.

Now try to bring the tablespace online, at this point you will get the error that datafile 4 needs media recovery.

issue the following command to recover the tablespace, please note that the database itself can remain open.

SQL>recover tablespace users;
media recovery completed.

now bring the tablespace online.

SQL>alter tablespace users online;

2.1.2. What is the difference between alter database recover and sql*plus recover command?

ALTER DATABASE recover is useful when you as a user want to control the recovery. SQL*PLUS recover command is useful when we prefer automated recovery.

Chapter 3. Duplicate database with control file

What are the steps required to duplicate a database with control file?

Copy initSID.ora to the new initXXX.ora file. i.e.,

cp $ORACLE_HOME/dbs/inittest.ora $ORACLE_HOME/dbs/initDUP.ora

Edit the parameters that are specific to location and instance:-

db_name = dup
instance_name = dup
control_files = change the location to point to dup
background_dump_dest = change the location to point to dup/bdump
core_dump_dest = change the location to point to dup/cdump
user_dump_dest = change the location to point to dup/udump
log_archive_dest_1 = dup/archive
db_file_name_convert = (test, dup)
log_file_name_convert = (test, dup)
remote_login_passwordfile = exclusive

Actual settings :-

*.background_dump_dest=’/u02/app/oracle/admin/DUP/bdump’
*.compatible=’10.1.0.2.0′
*.control_files=’/u02/app/oracle/oradata/DUP/control01.ctl’,'/u02/app/oracle/oradata/DUP/control02.ctl’,'/u02/app/oracle/oradata/DUP/control03.ctl’
*.core_dump_dest=’/u02/app/oracle/admin/DUP/cdump’
*.db_block_size=8192
*.db_cache_size=25165824
*.db_domain=”
*.db_file_multiblock_read_count=16
*.db_name=’DUP’
*.db_recovery_file_dest=’/u02/app/oracle/flash_recovery_area’
*.db_recovery_file_dest_size=2147483648
*.dispatchers=’(PROTOCOL=TCP) (SERVICE=DUPXDB)’
*.java_pool_size=50331648
*.job_queue_processes=10
*.large_pool_size=8388608
*.log_archive_dest_1=’LOCATION=/u02/app/oracle/oradata/payroll MANDATORY’
*.open_cursors=300
*.pga_aggregate_target=25165824
*.processes=250
*.shared_pool_size=99614720
*.sort_area_size=65536
*.undo_management=’AUTO’
*.undo_tablespace=’UNDOTBS1′
*.user_dump_dest=’/u02/app/oracle/admin/DUP/udump’
*.remote_login_passwordfile=exclusive
*.db_file_name_convert = (test, dup)
*.log_file_name_convert =(test,dup)

Make the directories for the dump destination:-

oracle@debian:/u02/app/oracle/admin/DUP$ mkdir bdump
oracle@debian:/u02/app/oracle/admin/DUP$ mkdir cdump
oracle@debian:/u02/app/oracle/admin/DUP$ mkdir udump

Make a directory to hold control files, datafiles and such:-

oracle@debian:/u02/app/oracle/oradata/PRD$ cd ..
oracle@debian:/u02/app/oracle/oradata$ mkdir DUP

Ensure that the oracle sid is pointing to the right Database. Make an ora password file so that other users can connect too.

export ORACLE_SID=DUP
$orapwd file=$ORACLE_HOME/dbs/orapw$ORACLE_SID password=easypass
sqlplus / as sysdba
sql>startup nomount;

oracle@debian:/u02/app/oracle/product/10.1.0/db_1/dbs$ sqlplus / as sysdba;

SQL*Plus: Release 10.1.0.2.0 – Production on Wed Aug 24 21:05:26 2005

Copyright (c) 1982, 2004, Oracle. All rights reserved.

Connected to an idle instance.

SQL> startup nomount;
ORACLE instance started.

Total System Global Area 188743680 bytes
Fixed Size 778036 bytes
Variable Size 162537676 bytes
Database Buffers 25165824 bytes
Redo Buffers 262144 bytes
SQL>

Check net8 connectivity sqlplus sys/easypass@dup if that goes through successfully then exit. The idea is to check for sql*net connectivity.

if you get ORA-12154: TNS:could not resolve the connect identifier specified then more work needs to be done.
DUP =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = debian)(PORT = 1521))
(CONNECT_DATA =
(SERVICE_NAME = dup)
)

$tnsping dup
Used TNSNAMES adapter to resolve the alias
Attempting to contact (DESCRIPTION = (ADDRESS = (PROTOCOL = TCP)(HOST = debian)(PORT = 1521)) (CONNECT_DATA = (SERVICE_NAME = dup)))
OK (0 msec)

Even with this if you are getting ORA-12528: TNS:listener: all appropriate instances are blocking new connections then we have to connect to the auxiliary (the database to be duplicated as / ) and the target database ( source ) with user/pass@test
start duplicating the database. export ORACLE_SID=DUP

rman target sys/easypass@test auxiliary /
run{
allocate auxiliary channel ch1 type disk;
duplicate target database to dup;
}

oracle@debian:/u02/app/oracle/product/10.1.0/db_1/network/admin$ rman target sys/kernel@test auxiliary /

Recovery Manager: Release 10.1.0.2.0 – Production

Copyright (c) 1995, 2004, Oracle. All rights reserved.

RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-00554: initialization of internal recovery manager package failed
RMAN-04005: error from target database:
ORA-01017: invalid username/password; logon denied

The work around to this is to create a user with dba privileges and connect through that users id .

$export ORACLE_SID=test
SQL>grant sysdba to mhg;

oracle@debian:/u02/app/oracle/product/10.1.0/db_1/network/admin$ rman target mhg/mhg@test auxiliary /

Recovery Manager: Release 10.1.0.2.0 – Production

Copyright (c) 1995, 2004, Oracle. All rights reserved.

connected to target database: TEST (DBID=1843143191)
connected to auxiliary database: DUP (not mounted)

oracle@debian:~$ rman target mhg/mhg@test auxiliary / @run.rcv

Recovery Manager: Release 10.1.0.2.0 – Production

Copyright (c) 1995, 2004, Oracle. All rights reserved.

connected to target database: TEST (DBID=1843143191)
connected to auxiliary database: DUP (not mounted)

RMAN> run{
2> allocate auxiliary channel c1 type disk;
3> duplicate target database to dup;
4> }
5>
using target database controlfile instead of recovery catalog
allocated channel: c1
channel c1: sid=270 devtype=DISK

Starting Duplicate Db at 24-AUG-05
released channel: c1
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03002: failure of Duplicate Db command at 08/24/2005 21:13:09
RMAN-05501: aborting duplication of target database
RMAN-05001: auxiliary filename /u02/app/oracle/oradata/test/users01.dbf conflicts with a file used by the target database

This error is primarily because the files of the test database are already present, this is a bad thing we have to use db_file_name_convert and long_file_name_convert to overcome these errors.

This is the final run output:-

oracle@debian:~$ rman target mhg/mhg@test auxiliary /

Recovery Manager: Release 10.1.0.2.0 – Production

Copyright (c) 1995, 2004, Oracle. All rights reserved.

connected to target database: TEST (DBID=1843143191)
connected to auxiliary database: DUP (not mounted)

RMAN> @run.rcv

RMAN> run{
2> allocate auxiliary channel c1 type disk;
3> duplicate target database to dup;
4> }
using target database controlfile instead of recovery catalog
allocated channel: c1
channel c1: sid=270 devtype=DISK

Starting Duplicate Db at 24-AUG-05

contents of Memory Script:
{
set until scn 2150046;
set newname for datafile 1 to
“/u02/app/oracle/oradata/DUP/system2.dbf”;
set newname for datafile 2 to
“/u02/app/oracle/oradata/DUP/undotbs01.dbf”;
set newname for datafile 3 to
“/u02/app/oracle/oradata/DUP/sysaux01.dbf”;
set newname for datafile 4 to
“/u02/app/oracle/oradata/DUP/users01.dbf”;
restore
check readonly
clone database
;
}
executing Memory Script

executing command: SET until clause

executing command: SET NEWNAME

executing command: SET NEWNAME

executing command: SET NEWNAME

executing command: SET NEWNAME

Starting restore at 24-AUG-05

channel c1: starting datafile backupset restore
channel c1: specifying datafile(s) to restore from backup set
restoring datafile 00001 to /u02/app/oracle/oradata/DUP/system2.dbf
restoring datafile 00002 to /u02/app/oracle/oradata/DUP/undotbs01.dbf
…………..
datafile copy filename=/u02/app/oracle/oradata/DUP/sysaux01.dbf recid=2 stamp=567206656

cataloged datafile copy
datafile copy filename=/u02/app/oracle/oradata/DUP/users01.dbf recid=3 stamp=567206656

datafile 2 switched to datafile copy
input datafilecopy recid=1 stamp=567206656 filename=/u02/app/oracle/oradata/DUP/undotbs01.dbf
datafile 3 switched to datafile copy
input datafilecopy recid=2 stamp=567206656 filename=/u02/app/oracle/oradata/DUP/sysaux01.dbf
datafile 4 switched to datafile copy
input datafilecopy recid=3 stamp=567206656 filename=/u02/app/oracle/oradata/DUP/users01.dbf

contents of Memory Script:
{
Alter clone database open resetlogs;
}
executing Memory Script

database opened
Finished Duplicate Db at 24-AUG-05

RMAN> **end-of-file**

This ends a successful duplication of a database without control file.

Chapter 4. Using rman tocheck logical and physical block corruption

To generate block corruption you can use the dd unix utility
caution, it will corrupt your block(s):-
$dd if=/dev/null of=/u02/oradata/myrac/anyfile.dbf bs=8192 conv=notrunc seek=10 count=1
seek=10 write at block 10, count=1 write to only that block
now you can run dbv to verify that the blocks are actually corrupt
and then recover the datafile by using oracle’s blockrecover command.

export ORACLE_HOME=test
rman target /
run {
allocate channel d1 type disk;
backup check logical validate database;
release channel d1;
}
To validatea datafile(s) :-
run {
allocate channel d1 type disk;
backup check logical validate datafile 1,2;
release channel d1;
}

During this command every block is written to memory and then subsequently rewriten to another portion of the memory, during
this memory to memory write every block is checked for corruption.
RMAN’s backup command with validate and check logical clause allow to quickly validate for both physical and logical corruption.

Chapter 5. Checking for datafile corruption

A corrupted block requires dropping an object. The message identifies the block in error by file number and block number. The cure has always been to run a query such as: SELECT owner, segment_name, segment_type FROM dba_extents WHERE file_id = AND BETWEEN block_id AND block_id + blocks – 1; where and were the numbers from the error message. This query indicates which object contains the corrupted block. Then, depending on the object type, recovery is either straightforward (for indexes and temporary segments), messy (for tables), or very messy (for active rollback segments and parts of the data dictionary). In Oracle 9i Enterprise Edition, however, a new Recovery Manager (RMAN) command, BLOCKRECOVER, can repair the block in place without dropping and recreating the object involved. After logging into RMAN and connecting to the target database, type: BLOCKRECOVER DATAFILE filenumber BLOCK blocknumber; A new view, V$DATABASE_BLOCK_CORRUPTION, gets updated during RMAN backups, and a block must be listed as corrupt for a BLOCKRECOVER to be performed. To recover all blocks that have been marked corrupt, the following RMAN sequence can be used: BACKUP VALIDATE DATABASE; BLOCKRECOVER CORRUPTION LIST; This approach is efficient if only a few blocks need recovery. For large-scale corruption, it’s more efficient to restore a prior image of the datafile and recover the entire datafile, as before. As with any new feature, test it carefully before using it on a production database.

run {
allocate channel ch1 type ;
blockrecover datafile block ;
}

1. What are the steps to start the database from a text control file?
1.1. What are the steps required to start a database from text based control file?
1.2. Give a complete scenario of backup, delete and restore.
1.3. How do I backup archive log?
1.4. How do I do a incremental backup after a base backup?
1.5. What is ORA-002004 error?
1.6. What Information is Required for RMAN TAR?
1.7. How To turn Debug Feature on in rman?
1. What are the steps to start the database from a text control file?
1.1. What are the steps required to start a database from text based control file?
1.2. Give a complete scenario of backup, delete and restore.
1.3. How do I backup archive log?
1.4. How do I do a incremental backup after a base backup?
1.5. What is ORA-002004 error?
1.6. What Information is Required for RMAN TAR?
1.7. How To turn Debug Feature on in rman?

1.1. What are the steps required to start a database from text based control file?

ALTER DATABASE BACKUP CONTROLFILE TO ‘/oracle/backup/cf.bak’ REUSE; –or to a file name on the OS. With this command you will get a text based version of your control file. REUSE clause specifies Oracle to overwrite the control files. If we ignore this option Oracle will not overwrite the control file if it is already present in the directory specified by the initSID.ora file.

Start the database in nomount mode. If you have 3 control file entries in pfile / spfile you will get 3 new control files.

Now run the control file script to create your control files.

recover database using backup controlfile until cancel

1.2. Give a complete scenario of backup, delete and restore.

Given that you want to take a base level backup, simulate complete failure by removing controlfile, datafile, redo log, archive log, these are the steps to be followed.

First take a base level backup of the database.

backup incremental level=0 database;

Simulate media failure by removing the control file and data file. sqlplus / as sysdba; shutdown immediate; exit; rm control* system*

When we don’t have a control file the problem becomes quite complex the reason been that the rman backup information is stored in the control file. So when we don’t have the control file we won’t have the information about backups. First step should be towards restoring the control file. Fortunately we can do a listing in our flash recovery area and guess which backup piece has the information about our control file. In my box following is the listing on the flash recovery area:-

/u02/app/oracle/flash_recovery_area/TEST/backupset/2005_07_30/
o1_mf_ncnn0_TAG20050730T130722_1gqn4jy2_.bkp
o1_mf_nnnd0_TAG20050730T130722_1gqmzdjz_.bkp
now I am assuming xxcnn0xxx has the control file information in it.

We have to use a nifty pl/sql program to recover our control file, once it is done successfully then we can go on our merry way using rman to recover the rest of the database.

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) :=
‘/u02/app/oracle/flash_recovery_area/TEST/backupset/2005_07_30/o1_mf_ncnn0_TAG20050730T130722_1gqn4jy2_.bkp’;
v_maxPieces := 1;
— 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=>’/u02/app/oracle/oradata/test/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;
/

Pl/SQL completed successfully. I had 3 control files, the above command will restore only one control file so I will do a operating system copy to restore the rest of the control files. cp control01.ctl control02.ctl cp control01.ctl control03.ctl

After control file is restored launch rman and list all the backup information.,

rman target /
rman>sql ‘ alter database mount’;
rman>list backup;
BS Key Type LV Size Device Type Elapsed Time Completion Time
——- —- — ———- ———– ———— —————
21 Incr 0 2G DISK 00:02:39 30-JUL-05
BP Key: 21 Status: AVAILABLE Compressed: NO Tag: TAG20050730T130722
Piece Name: /u02/app/oracle/flash_recovery_area/TEST/backupset/2005_07_30/o1_mf_nnnd0_TAG20050730T130722_1gqmzdjz_.bkp List of Datafiles in backup set 21
File LV Type Ckp SCN Ckp Time Name
—- — —- ———- ——— —-
1 0 Incr 1723296 30-JUL-05 /u02/app/oracle/oradata/test/system2.dbf
2 0 Incr 1723296 30-JUL-05 /u02/app/oracle/oradata/test/undotbs01.dbf
3 0 Incr 1723296 30-JUL-05 /u02/app/oracle/oradata/test/sysaux01.dbf
4 0 Incr 1723296 30-JUL-05 /u02/app/oracle/oradata/test/users01.dbf

The above command indicates that the backup set key is 21 and tag is blah and time is blah.

Connect to rman target / restore database; recover database; exit;

sqlplus / as sysdba; startup; Now the database should have been recovered to your current SCN at which time we encountered a complete media failure.

1.3. How do I backup archive log?

In order to backup archivelog we have to do the following:-

run {
backup
(archivelog all delete input);
}

If you want to delete archive logs ignoring those that were inaccesible after backup you have to use (archivelog all skip inaccessible delete input);

1.4. How do I do a incremental backup after a base backup?

RMAN> backup incremental level=1 database plus archivelog delete all input;

This will take a incremental backup of the database and make a copy of archivelog and delete all input.

1.5. What is ORA-002004 error?

A disk I/O failure was detected on reading the controlfile.

Basically check whether the control file is available, permissions
are right on the control file,
spfile/init.ora right to the right location, if all checks were
done still you are getting the error, then from the multiplexed
control file overlay on the corrupted one, let us say you have
three control files control01.ctl, control02.ctl and control03.ctl
and now you are getting errors on control03.ctl then just cp control01.ctl
over to control03.ctl and you should be all set.
In order to issue
ALTER DATABASE BACKUP CONTROLFILE TO TRACE;
database should be mounted and in our case it is not mounted then the only
other option available is to restore control file from backup or cp the
multiplexed control file over to the bad one.

1.6. What Information is Required for RMAN TAR?

Hardware Configuration
* The name of the node that hosts the database
* The make and model of the production machine
* The version and patch of the operating system
* The disk capacity of the host
* The number of disks and disk controllers
* The disk capacity and free space
* The media management vendor (if you use a third-party media manager)
* The type and number of media management devices
Software Configuration
* The name of the database instance (SID)
* The database identifier (DBID)
* The version and patch release of the Oracle database server
* The version and patch release of the networking software
* The method (RMAN or user-managed) and frequency of database backups
* The method of restore and recovery (RMAN or user-managed)
* The datafile mount points

You should keep this information both in electronic and hardcopy form. For example, if you save this information in a text file on the network or in an email message, then if the entire system goes down, you may not have this data available.

1.7. How To turn Debug Feature on in rman?

run {
allocate channel c1 type disk;
debug on;
}
rman>list backup of database;

You will see a output similar to
DBGMISC: ENTERED krmkdftr [18:35:11.291]

DBGSQL: EXEC SQL AT TARGET begin dbms_rcvman . translateDataFile (
:fno ) ; end ; [18:35:11.291]
DBGSQL: sqlcode=0 [18:35:11.300]
DBGSQL: :b1 = 1
DBGMISC: ENTERED krmkgdf [18:35:11.301]
DBGMISC: ENTERED krmkgbh [18:35:11.315]
DBGMISC: EXITED krmkgbh with status Not required – no flags
[18:35:11.315] elapsed time [00:00:00:00.000]
DBGMISC: EXITED krmkgdf [18:35:11.315] elapsed time [00:00:00:00.014]
DBGMISC: EXITED krmkdftr [18:35:11.315] elapsed time [00:00:00:00.024]
DBGMISC: EXITED krmknmtr with status DF [18:35:11.315] elapsed time
[00:00:00:00.024]
DBGMISC: EXITED krmknmtr with status DFILE [18:35:11.315] elapsed time
[00:00:00:00.024]
DBGMISC: EXITED krmknmtr with status backup [18:35:11.315] elapsed time
[00:00:00:00.024]
DBGMISC: krmknmtr: the parse tree after name translation is:
[18:35:11.315]
DBGMISC: EXITED krmknmtr with status list [18:35:11.316] elapsed time
[00:00:00:00.078]
DBGMISC: krmkdps: this_reset_scn=1573357 [18:35:11.316]
DBGMISC: krmkdps: this_reset_time=19-AUG-06 [18:35:11.316]
DBGMISC: krmkdps: untilSCN= [18:35:11.317]

You can always turn debug off by issuing

rman>debug off;