RE: FW: backing up rman catalog for disaster recovery

I agree that an RMAN scripted backup controlfile is not useful, but configuring RMAN controlfile autobackup does help:

1. You then don't have to include a copy command (internal or external) for you controlfile as RMAN does it for you automatically.
2. The filename of the autobackup contains both the date and the database ID in a human readable format.

To get your controlfile back (without needing a catalog) you just need to do

RMAN> restore controfilefile from '<name of autobackup file>';

• Charlotte

---

>>I just cheated and backed up the control file separately

"Cheat" nothing this is just smart...or reality :o|

>> run {allocate channel c4 type disk; copy current controlfile to...

>> in my shell script *every* time and AT THE END OF EACH BACKUP

>> NOT an RMAN *backup* of my controlfile (totally useless), 

>> but rather a *COPY* of my controlfile. 

>> Meaning it can be used without RMAN;

As I said in an earlier post, RMAN backup controlfile (IMHO) is rather useless.

It is the classic "chicken and egg".

You have a controlfile in the RMAN backup, but you need a current controlfile to get to the backup! (in the absence of a recover catalog). If I have a current controlfile then why do I need the one *in* the backup? 

Oracle should update the RMAN documentation it indicate thsi mental puzzle.

Seems everyone learns this the hard way during testing...or the really hard way during a disaster.

Anyone want to guess...

What would be of some use when all current controlfiles and datafiles are lost and you have >1 good RMAN backups? (A worst case senario).

 

Chris Marquez

Oracle DBA

 

-----Original Message-----

From: oracle-l-bounce_at_freelists.org on behalf of Dennis Williams

Sent: Wed 5/25/2005 6:15 PM

To: rgramolini_at_tax.state.vt.us

Cc: oracle-l

Subject: Re: FW: backing up rman catalog for disaster recovery



Actually, RMAN always writes to the control file before it updates the

catalog. So even if you do an RMAN backup using a catalog, you can

still recover the database using only the controlfile. Now, in

Oracle8i I had problems recovering the control file from the RMAN

backup, so I just cheated and backed up the control file separately

after the RMAN backup completed, and made sure the control file backup

was on the same tape as the RMAN backup. I have performed many

recoveries using this method.

Dennis Williams

On 5/25/05, Ruth Gramolini <rgramolini_at_tax.state.vt.us> wrote:

>=20

>=20



> One very easy way is to do an rman backup with the nocatalog option. Thi=


s



> will use controlfile info for restores and recoveries. You can use all t=


he



> options of rman, just no catalog. That is what we do.


>=20



> Just my $0.02,




> Ruth


>=20



> -----Original Message-----




> From: Paula_Stankus_at_doh.state.fl.us




> [mailto:Paula_Stankus_at_doh.state.fl.us]




> Sent: Wednesday, May 25, 2005 4:49 AM




> To: Paula_Stankus_at_doh.state.fl.us; rgramolini_at_tax.state.vt.us;




> all_about_oracle_at_hotpop.com; oracle-l_at_freelists.org




> Subject: RE: backing up rman catalog for disaster recovery


>=20

>=20



> I am setting up a disaster recovery site and I was thinking about the




> best way to do this.


>=20



> My theory is that I would like to not just use another recovery catalog




> on the DR site to backup my primary catalog but to somehow keep these




> catalogs constantly in-synch so when I do need to do complete recovery




> and only have the secondary rman catalog available - I wouldn't have to




> recover the catalog as all of the previous backups would be found there.


>=20



> So....should I do this using Oracle Data Guard on my disaster recovery




> site catalog or backup rman then restore as my first procedure? Any




> advice?


>=20



> --




> http://www.freelists.org/webpage/oracle-l


>

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