What is Level 0, Level 1 backup?
A level 0 incremental backup, which is the base for subsequent incremental backups, copies all blocks containing data, backing the data file up into a backup set just as a full backup would. A level 1 incremental backup can be either of the following types:
A differential backup, which backs up all blocks changed after the most recent incremental backup at level 1 or 0
A cumulative backup, which backs up all blocks changed after the most recent incremental backup at level 0
How do you set up the RMAN tape backups?
Configure the channel as SBT_TAPE and use the “ENV” parameter to set the tape configurations.
How do I go about backing up my online redo logs?
You don’t. Online redo logs should never, ever be included in a backup, regardless of whether that backup is performed hot or cold. The reasons for this are two-fold. First, you physically cannot backup a hot online redo log, and second, there is precisely zero need to do so in the first place because an archive redo log is, by definition, a backup copy of a formerly online log. There is, however, a more practical reason: backing up the online logs yourself increases the risk that you will lose…
What is a backup set?
RMAN can store backup data in a logical structure called a backup set, which is the smallest unit of an RMAN backup. A backup set contains the data from one or more data files, archived redo logs, control files, or server parameter files.
What is a Channel? How do you enable the parallel backups with RMAN?
Use the ALLOCATE CHANNEL command to manually allocate a channel, which is a connection between RMAN and a database instance. To enable the parallel backups, allocate multiple manual channels in the run block or configure parallelism
CONFIGURE DEVICE TYPE DISK PARALLELISM 4 BACKUP TYPE TO BACKUP SET;
What is an auxiliary channel in RMAN? When do you need this?
An auxiliary channel is a link to an auxiliary instance. If you do not have automatic channels configured, then before issuing the DUPLICATE command, manually allocate at least one auxiliary channel within the same RUN command. When a Duplicate Database is created or tablespace point-in-time recovery is performed Auxiliary database is used. This database can be either on the same host or a different host.
What is the init parameter that specifies the minimum number of days that Oracle keeps backup information in the control file?
You can use the CONTROL_FILE_RECORD_KEEP_TIME parameter to specify the minimum number of days that Oracle keeps this information in the control file
What is the difference between validate and crosscheck?
The restore … validate and validate backup set commands test whether you can restore backups or copies. You should use:
– restore … validate when you want RMAN to choose which backups or copies should be tested.
– validate the backup set when you want to specify which backup sets should be tested.
Is it possible to specific tables when using the RMAN DUPLICATE feature? If yes, how?
No, table-based recovery is not possible in the RMAN duplicate command.
Outline the steps involved in CANCEL-based recovery from the full database from hot backup.
RMAN doesn’t support cancel-based recovery as SQL*plus does.
Outline the steps involved in SCN-based recovery from the full database from hot backup.
startup mount;
restore database UNTIL SCN 233545;
recover database UNTIL SCN 233545;
alter database open re set logs;
Outline the steps involved in TIME-based recovery from the full database from hot backup.
startup mount;
restore database UNTIL TIME “TO_DATE(’28/12/2012 18:00:00′, ‘DD/MM/YYYY HH24:MI:SS’)”;
recover database UNTIL TIME “TO_DATE(’28/12/2012 18:00:00′, ‘DD/MM/YYYY HH24:MI:SS’)”;
alter database open resetlogs;
Explain the steps to perform the point-in-time recovery with a backup that is taken before the resetlogs of the DB?
- We need to list the database incarnations by using the list incarnation command.
- shutdown the database
- startup mount the database
- Issue reset database to incarnation to reset the incarnation.
- Restore the database using the restore command (e.g restore until scan 23243)
- 6. recover database
- Open the database using resetlogs command
RMAN> list incarnation of database;
RMAN>reset database to incarnation 5;
run
{
set until scn 234345;
restore database;
rec ….
Outline the steps for changing the DBID in a cloned environment.
shutdown Immediate
startup mount
Then, run the DBNEWID utility from the command line.
nid target =/
SQL> alter database open resetlogs;
How do you install the RMAN recovery catalog? or List the steps required to enable the RMAN
. backup for a target database?
Steps to be followed:
1) Create connection string at catalog database.
2) At the catalog database create one new user or use an existing user and give that user a recovery_catalog_owner privilege.
3) Login into RMAN with the connection string
- a) export ORACLE_SID
- b) rman target catalog @connection string
4) rman&g ….
List some of the RMAN catalog view names which contain the catalog information.
RC_DATABASE_INCARNATION, RC_BACKUP_COPY_DETAILS, RC_BACKUP_CORRUPTION, RC_BACKUP_DATAFILE_SUMMARY to name a few
What is the difference between obsolete RMAN backups and expired RMAN backups?
The term obsolete does not mean the same as expired. In short obsolete means “not needed ” whereas expired means “not found.”
A status of “expired” means that the backup piece or backup set is not found in the backup destination. A status of “obsolete” means the backup piece is still available, but it is no longer needed. The backup piece is no longer needed since RMAN has been configured to no longer need this piece after so many days have elapsed, or so many backups have been performed. ….
How do you verify the integrity of the image copy in the RMAN environment?
Use the below commands :
rman> catalog datafilecopy ‘f:testsystem.dbf’;
rman> backup validate check logical datafile ‘f:testsystem.dbf’;
SQL> SELECT * FROM v$database_block_corruption;
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Is it possible to take Catalog Database Backup using RMAN? If Yes, How?
A recovery catalog is a schema stored in a database that tracks backups and stores of target databases. So better to take an export backup How do you identify the expired, active, obsolete backups? Which RMAN commands do you use?
Obsolete backups:
RMAN> report obsolete;
expired backup:
RMAN> list expired backup;
Active database: RMAN> list backup
When do you use the crosscheck command?
Crosscheck will be useful to check whether the catalog information is intact with OS-level information.
How do you clone the database using RMAN? Give brief steps
Two commands are available in RMAN to clone the database:
1) Duplicate target database to …
2) Restore.
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