RMAN nocatalog

Hi Friends,

I have been backing up my database with RMAN nocatalog and it was fine. :)
What is the advantage of RMAN with catalog pls? What I can see is a disadvantage because you need to have another database for the catalog.
So you have also to protect it by backup it up with rman too? What will happen if the catalog crashes and you have no backup?;)

Thanks a lot

1)A recovery catalog is a schema stored in a database that tracks backups and stores scripts for use in RMAN backup.
2) Yes.. We have to protect the catalog database.if the catalog database is crashed you will lost the backup informations you kept in the catalog.if you have the backup of the catalog database you can restore the database.

If you use a catalog then your backup informatin stored in 2 places, control file and catalog. If you lose a catalog you still have you control file (some limitations on how far back you can go will apply). If you lose you control file , you still have a catalog and will be able to restore a control file.
If you do NOT have a catalog and lost your controlfiles, you should look for another job because most likely you will be fired.

Thanks New Friend, Just saw ur ID here :)

I'm a little confused about control files, how often do u backup the control files? if I have weekly backup of control files will I be able to use the week old control file if the current is lost?

By the way in my RMAN backup the control file is also included, how can I lose the control files if it is being backed up? :)


Thanks

If you lose all your live control files , your back info does not exists because it is stored in the very same control files that you just lost and in case u did not have a catalog you can not recover. If you do have a catalog, you can recover your controlfile, mount database and proceed with the database recovery.
This is classic interview question, you would not pass !

can not recover? - what utter utter rubbish

I think you can recover from control file loss in no catalog mode provided you have configured "controlfile autobackup on"

Please see "Table 2-25 RESTORE CONTROLFILE Scenarios" table from below link.
http://download-west.oracle.com/docs...rcmsynta46.htm

Quote:

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Originally Posted by davey23uk

can not recover? - what utter utter rubbish

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So how do you suggest one would restore a database in a case when original server and disks are gone and you need to restore your database on another server ? Can you do it if your rman backup is done in nocatalog mode?

I am not going to judge your technical skills , perhaps they are very good. It is possible that I made a mistake(u did not prove me wrong yet). Even it all this is true, it does not warrant a language you are using in response. After all this is a forum to exchange opinions .
Respect others and you will be respected .

Quote:

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Originally Posted by paragp1981

I think you can recover from control file loss in no catalog mode provided you have configured "controlfile autobackup on"

Please see "Table 2-25 RESTORE CONTROLFILE Scenarios" table from below link.
http://download-west.oracle.com/docs...rcmsynta46.htm

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Yes, you can restore from autobackup. I missed that. But what if autobackup location is gone too? Imagine you have all your rman backups sitting on the tape(netbackup or whatever other tsm ) and no controlfile! How would you restore your database?

Hi

The trick is to know the dbid and restore the controlfile from your tape backups

Code:

---

rman target /
set dbid
startup nomount;
run
{
allocate channel ch1sbt_tape type sbt;
set controlfile autobackup format for device type sbt to
'path_to_controlfile/%F';
restore controlfile from autobackup;
release channel ch1_tape;
}

---

You need to store the dbid somewhere otherwise i am afraid you are lost.

regards
Hrishy

Quote:

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Originally Posted by hrishy

Hi

The trick is to know the dbid and restore the controlfile from your tape backups

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It's not a trick - its a fully documented, fully supported method of recovery

Quote:

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Originally Posted by davey23uk

It's not a trick - its a fully documented, fully supported method of recovery

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ahh the english language :-)

regards
Hrishy

Quote:

---

Originally Posted by hrishy

Hi

The trick is to know the dbid and restore the controlfile from your tape backups

Code:

---

rman target /
set dbid
startup nomount;
run
{
allocate channel ch1sbt_tape type sbt;
set controlfile autobackup format for device type sbt to
'path_to_controlfile/%F';
restore controlfile from autobackup;
release channel ch1_tape;
}

---

You need to store the dbid somewhere otherwise i am afraid you are lost.

regards
Hrishy

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Just curios,assuming that sbt channel is just a tape deivce and not a tape management system, how would rman know which file to request base on just a dbid? It got to be stored somewhere, but where?

I think I may know an answer for my own question. RMAN probably generate an unique backup control file name based on dbid and therefore if it knows dbid it can generate this name and request backup file from the tape.

Regardless if AUTOBACKUP is set to ON or not, if you are doing a full database backup, the controlfile is going to be backed up.

Now assuming you are in nocatalog mode and simply loose the backed up controlfile, you can still recover from a backup with the help of the DBMS_BACKUP_RESTORE package.

Right. There was one unpublised document available in metalink. Get hold of support they can help you out on this.

Regards,
Satheesh Babu S
http://satheeshbabus.blogspot.com

Hi

We usually put the rman logfile along with the backup to the tape.
In the logfile look for something like

Code:

---

copying current controlfile
output filename=/backup/SID_xxx_.back

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You can just copy the controlfile to the location in the place as indicated by init.ora and try to bring up the database to mountstate.

If you are on 10g you can also

Code:

---

set DBID=<>
run
{
allocate channel cht_t1 device type sbt tape;
restore controlfile
from
'/backup/SID_xxx_.back'
}

---

regards
Hrishy

Quote:

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Originally Posted by ebrian

Regardless if AUTOBACKUP is set to ON or not, if you are doing a full database backup, the controlfile is going to be backed up.

Now assuming you are in nocatalog mode and simply loose the backed up controlfile, you can still recover from a backup with the help of the DBMS_BACKUP_RESTORE package.

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Hi Ebrian,

I think your note is the most REMARKABLE here :cool:
So, am I justified if I continue my backup system with nocatalog mode?
Would it make be still a good DBA?:o


Thanks a lot

It is actually up to you, I see no reason not to use a catalog even alternative ways to restore your database do exist.
Let me ask you a question, why not to use it? What are you trying to save?

Hi,
If number of DB to be backed up is more in your shop, then it make sense to use Catalog DB. Otherwise use nocatalog.

Regards,
Satheesh Babu S
http://satheeshbabus.blogspot.com

Quote:

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Originally Posted by BV1963

It is actually up to you, I see no reason not to use a catalog even alternative ways to restore your database do exist.
Let me ask you a question, why not to use it? What are you trying to save?

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Correction: Ebrian's remark is the most remarkable I mean
Hi,

The fact that you have to create another database for the catalog is cumbersome plus u have to protect the 2nd maybe by another rman catalog like a chain reaction?


Thanks

Quote:

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Originally Posted by reeshe

Correction: Ebrian's remark is the most remarkable I mean
Hi,

The fact that you have to create another database for the catalog is cumbersome plus u have to protect the 2nd maybe by another rman catalog like a chain reaction?


Thanks

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U do not have to protect it because you still have a controlfiles, and u considering NOT TO HAVE a catalog, so why are you so concerned with protecting a catalog?
Secondly, it is not ac umbersome , just create a another small database.
You greatly reduce you chances for a problem since catalog database and all of your controlfile are not likely to be lost at the same time.
In summary....It is really your choice. If you feel that it is not worth the efforts... Let me ask you, did you ever have to restore a production database without a catalog? Do you want to have that experience?