RMAN Interview Questions

Incaranation help to go backup to old position of the database.

DBID means database id.Incunation means:  Database incarnation is effectively a new “version” of the database that happens when you reset the online redo logs using “alter ...

Logical backup means backup of tablespace in the form of binary but physical backup means backup of databfile, controlfile, logfile, spfile

In Oracle Logical Backup is "which is taken using either Traditional Export/Import or Latest Data Pump". Where as Physical backup is known "when you take Physical O/s Database related Files as Backup".

The steps are: 1) Shutdown the database 2) Restore data files 3) Mount the database 4) Recover the database (sql> recover database until time 2005-12-14:12:10:03 Time base) (sql> recover database unti...

nid utility is use to change DBID and SID

Note:
Mount the databse
$export ORACLE_SID=test
$ nid target=system/manager
It will change and automaticaly generate new id and asign it to the database.

It is possible to use RMAN duplicate features to specific tables,with RMAN Duplicate we first create a target or duplicate single instance database and then convert the single instance database to a RAC database.

Obsolete: means the backup piece is still available,but it is no longer needed.It depends on retention policy,i,e.recovery window .

Expired: means the backup piece or backup set is not found in the backup destination.

The term obsolete does not mean the same as expired. In short, obsolete means "not needed," whereas expired means "not found."

run rman BACKUP INCREMENTAL LEVEL 1 FOR RECOVER OF COPY WITH TAG incr_update DATABASE; RECOVER COPY OF DATABASE WITH TAG incr_update; If this is the first time to run it will create an incremental...

In 10g You can minimize backup time By "duration 00:30 minimize time;"

run{backup format /complete path duration 00:30 minimize time database}

ADD CHANNELS FOR IMPROVE PERFORMANCE ...

Start the database in MOUNT mode RMAN>restore database; then if the online redo logs are intact then RMAN>recover database; if the online redo logs are not intact/not available then RMAN>recover dat...

We don't need to recover a database if it were a consistent backup (cold).

But You should make sure to shutdown the DB with options available other than
Abort.

Allocate channels / parallelism.

You can use incremental backup either differential or accumalative. so you dont have to backup the whole database everytime just the changes made

Create pfile from spfile Edit pfile with _allow_resetlog_currpuation=true 1) Connect / as sysdba 2) Startup 3) Recover database until cancel; 4) Alter database open resetlogs; In RMAN restore: RMAN...

The encryption of backup sets by using one of the algorithms listed in V$RMAN_ENCRYPTION_ALGORITHMS. RMAN can transparently encrypt data written to backup sets and decrypt those backup sets when they ...

startup nomount pfile='/data01/init.ora'
run create controlfile script SQL>@create_control.sql
SQL>recover database using backup controlfile until cancel;
then after recovery SQL>alter database open resetlogs

when there is no down time for database (24/7) ,we should go for hot backup.

pre-req:database must be in archive log mode

Database should me archive log mode. 

connect to the catalog database and issue following query. it will list the target databases registered and manged by the catalog databases.

SQL> select name,dbid from rc_database;

You only can get information about one particular database at a time, after connecting with RMAN using target as that particular database.
Suppose there are three db A,B,C.

RMAN> connect target userA/pwd

Now whatever query you will execute will only give information about that database A only.

RMAN keeps the backup information in control file if we using RMAN w/o catalog.

in CATALOG mode , all the information about backup stores in catalog and database stores in target but in NOCATALOG mode , all the info stored in control file.

If you already have copy of datafile using OS command, then you can let RMAN know about it using command "CATALOG".

We have copy of datafile "user01.dbf" using OS.

RMAN> Connect target=/
RMAN> CATALOG datafilecopy 'C:/Backup/users01.dbf';

For verification:
RMAN> LIST COPY

1) RMAN>crosscheck backup;

This command will give you the output for the Active and Expired Backups.


2) RMAN>report obsolete;

This command will shows you the obsolete backups.

Use command:
Rman > crosscheck backup;
Rman > crosscheck archivelog all;
Rman > list backup;
Rman > list archive logall;

RMAN>list backup;

Above command gives you the information about RMAN backups.

Use this SQL to check

SQL> SELECT sid,totalwork,sofar FROM v$session_longops
WHERE sid=153;

Here give SID when back start it will show SID

Steps to be followed: 1) Create connection string at catalog database. 2) At catalog database create one new user or use existing user and give that user a recovery_catalog_owner privi...

Steps to be followed: 1) Create connection string at catalog database. 2) At catalog database, create one new user or use existing user and give that user a recovery_catalog_owner privilege.3) Login...

Central Repository Incremental Backup Corruption Detection Advantage over tradition backup system: 1). copies only the filled blocks i.e. even if 1000 blocks is allocated to datafile but...

 Advantage over tradition backup system:1).  copies  only the  filled  blocks  i.e. even if 1000 blocks is allocated to datafile but 500 are filled with data then RMAN wi...