RMAN Survey

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09-25-2001, 07:21 AM
Sureshy

Hi Friends...

I am wondering how many DBA' out there use RMAN and the direction in which it is going.

I do not use RMAN yet, I am backing up with traditional OS method. I am thinking of starting to back up using RMAN, mostly to build up my own knowledge and experience.

I was just wondering how many of you out there use it, what you think of it compared to other methods, and any thoughts on where it is going ?

I am already aware of concepts and application of RMAN so there is no need to detail this.

Thanks

Suresh
09-25-2001, 07:42 AM
dknight

I use it because it is easy to use.

RMAN with recovery catalog and export are my two methods of backup.
09-25-2001, 09:16 AM
marist89

I use it because it does the job and it's not another script I have to maintain. In addition, RMAN presents a universal interface to all media managers regardless of platform.
09-25-2001, 09:28 AM
omegamark

Now databases are not 30 or 40 or 50 gigs .Every Major database is 200 or 500 or in Terabytes ...

Rman does not copy the whole datafile .It copy's the datafile block by block and the empty blocks are not copied .Hear you save Time and the Tape space .This is one main Avantage .

The catalog database is having all the details about the backups .First few days till one is familiar RMAN will be a trouble (It generates of course lots of errors .that to when you have to relink the oracle with the media manager ...
Once it is done ....Rman is SMOOTH ....
09-25-2001, 09:56 AM
FARRUKH

I use RMAN because it is easy to setup, reliable and flexible. Another thing that we don't have to worry about is obsolete backup, oracle introduced a script to take care of obsolete backup check and delete from disk.

Cheers!

Farrukh
09-25-2001, 10:04 AM
omegamark

FARRUKH,

RMAN is not that easy to setup ..RMAN setting up to disk is child's play .But as a DBA you need to configure with the media manager and backup the databases to the tape .While relinking the oracle executables one should know as much as the OS administartion also ....

This differs from OS to OS ,version to version ...

It is just not create catalog .RAMN is set and running up ...

There is much more involved ...
09-25-2001, 10:11 AM
Raminder

Wonder what happens if the Recovery Catalog is lost along with Production database!

http://www.dbasupport.com/forums/sho...threadid=16051

Was'nt this guy better off without Rman? He would have had some cold backup at least.
09-25-2001, 10:25 AM
jodie

We use RMAN for most of the reasons stated above. It wasn't "easy" to get set up, but now that it is, it works great.

As far as loosing the Catalog as well as the production DB... That "shouldn't" happen. Oracle recommends that the Recovery catalog be placed on a DIFFERENT server than your Production DB. You should then plan for traditional OS backups of your Recovery Catalog.

Hope that helps!
Jodie
09-25-2001, 10:30 AM
marist89

Quote:

Originally posted by Raminder

Was'nt this guy better off without Rman? He would have had some cold backup at least.

This person's fundemental problem was that they kept the recovery catalog on the same database as was being backed up; a major no-no. This is a case where somebody setup RMAN but never fully tested possible recovery scenarios.
09-25-2001, 11:25 AM
sambavan

Quote:

Originally posted by omegamark

Rman does not copy the whole datafile .It copy's the datafile block by block and the empty blocks are not copied .

This depends on the type of backup you do. A full database backup would copy the entire datafile, including the empty blocks.

Level 0 would discard the empty blocks and only copy the used ones...

Quote:

Originally posted by omegamark

RMAN is not that easy to setup ..RMAN setting up to disk is child's play .But as a DBA you need to configure with the media manager and backup the databases to the tape .While relinking the oracle executables one should know as much as the OS administartion also ....

This is true to an extent only. i.e. it depends on the storage manager that you choose. Some storage mager clients gets relinked to the library libobk.* when you start the database instance, dynamically. Some would require a manual relink.
Once you pass this phase rest are all mostly straight forward.

Quote:

Originally posted by Raminder

Wonder what happens if the Recovery Catalog is lost along with Production database!

http://www.dbasupport.com/forums/sho...threadid=16051

Was'nt this guy better off without Rman? He would have had some cold backup at least.

As Jeff mentioned, he seems to have had both the production and catalog on the same server. It is always advised to have production and catalog in two different systems. Since I don't personally prefer to have an instance just dedicated for the backup, what I do is create catalog on two of my production instance and then do a cris-cross backup. That way, I'ld be loosing my backup only if my both the servers were to go down. I also would take a monthly level 0 on the OS level dump to the tape. That way you are better off.

[Edited by sambavan on 09-25-2001 at 11:53 AM]
09-25-2001, 11:41 AM
Raminder

It was me not Omegamark who posted the last one Sambavan.
Thanks for your guidance, though.
I feel I would be more in Control if I backed up on my own instead of using RMAN.

[Edited by Raminder on 09-25-2001 at 11:44 AM]
09-25-2001, 11:56 AM
Raminder

Originally posted by Sambavan:

Quote:

Since I don't personally prefer to have an instance just dedicated for the backup, what I do is create catalog on two of my production instance and then do a cris-cross backup. That way, I'ld be loosing my backup only if my both the servers were to go down

What happens to the poor ones with only one machine. Do you mean to say they should not use RMAN ?
09-25-2001, 11:57 AM
sambavan

Raminder, thanx for pointing the "post note" mistake. RMAN is a better tool and you would get to know the best of it when you do a recovery. My advice would be to create two test instances and try out on them. There are sample scripts under $ORACLE_HOME/rdbms/demo *.rcv *.sh which you can make use to start with.

My thanks to FARRUKH for pointing out the mistake in the directory location. Earlier it was $ORACLE_HOME/rdbms/admin. Made the correction now.

Sam

[Edited by sambavan on 09-25-2001 at 12:49 PM]
09-25-2001, 12:00 PM
sambavan

Quote:

Originally posted by Raminder
Originally posted by Sambavan:

Quote:

Since I don't personally prefer to have an instance just dedicated for the backup, what I do is create catalog on two of my production instance and then do a cris-cross backup. That way, I'ld be loosing my backup only if my both the servers were to go down

What happens to the poor ones with only one machine. Do you mean to say they should not use RMAN ?

Then you are taking the risk!!! I feel sorry for those poor soles.

Sam
09-25-2001, 12:44 PM
FARRUKH

RMAN scripts "*.rcv" are under $ORACLE_HOME/rdbms/demo directory.

Cheers!

Farrukh
09-25-2001, 12:57 PM
sonofsita

i am finding it easy to handle backups when I use rman with legato and with veritas backup exec. I criscrossed the catalog as I have two servers. if you do not have catalog also, if your version is 816 and above you have some new commands that help recover.look into them.Rman helps a lot.
the way it copies the written blocks helps reduce the time and space.