RE: FW: backing up rman catalog for disaster recovery

From: Marquez, Chris <cmarquez_at_collegeboard.org>
Date: Wed, 25 May 2005 21:38:04 -0400
Message-ID: <B30C2483766F9342B6AEF108833CC84E0450BBD3@ecogenemld50.Org.Collegeboard.local>

>>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
>

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



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

Received on Wed May 25 2005 - 21:45:19 CDT