Re: RMAN v Control Files

Bill:

Whether you use RMAN to Clone the database or run a Disk To Disk copy of a database and then recreate the control file, you can change the DBID. I may be wrong on this but, with 8i RMAN it does not reset the db_id, you have to do a reset database command of the clone, this will allow you to backup the clone with it RMAN being under the impression of being production. Now, you certainly would not want that, so, instead of using just one recovery catalog, use two, one for production and one for the cloned db's you have, or, use the controlfiles if you so desire.

With 9i, RMAN automatically resets the dbid so that you may use the same recovery catalog.

Now, if there is some sort of failure in RMAN with cloning the database, there is still the possibility of finishing the duplication process. Check out the Note id I posted. Basically what happens is you execute the following after creating the controlfile and have the db in mount stage:
  execute dbms_backup_restore.zeroDbid(0) you then shutdown immediate and recreate the controlfile again. The start it up again, open and select the db_id, it will be different. Now this method, i.e. executing the above package, is stated by Oracle as being unsupported. But for you clone or test instances, who really cares. Also, if you have to support one or two additional databases that are just recovery catalogs, it shouldn't be a big deal since they should be relatively small anyway, or, like I said before, use a catalog for production and then use the controlfiles for test instances, take your pick. I just don't agree with having to have mutliple recovery catalogs because of multiply dbid's, those id's can be taken care of.

HTH,
Pete's

The veiws expressed here are my own and not that of my employer.

"Bill & Mary Border" <bb22_at_adelphia.net> wrote in message news:<XG64a.9913$jR3.5134590_at_news1.news.adelphia.net>...
> We have other DB support group that copy datafiles and
> do not use DUPLICATE. Are you saying that there is a way
> to clone a database without DUPLICATE and then change
> the DBID?
>
> "Pete's" <empete2000_at_yahoo.com> wrote in message
> news:6724a51f.0302170612.5f734c17_at_posting.google.com...
> > The requirement of having multiple Recovery Catalogues is not
> > necessary. When you clone an instance, you are able to reset the
> > db_id of the database for versions 8i and above. Search metalinks for
> > "Reset DB_ID", check out Note Id: 174625.1 "RMAN: Incomplete
> > Duplication and It's Consequences". This dicusses how to change the
> > db_id. Therefore, you may register this new clone to rman with a
> > different db_id.
> >
> > HTH,
> > Pete's
> >
> > "Bill & Mary Border" <bb22_at_adelphia.net> wrote in message
> news:<lwW3a.9281$jR3.4947659_at_news1.news.adelphia.net>...
> > > If you're asking about the age-old question of whether
> > > or not to use an RMAN recovery catalog...
> > >
> > > Pros to using RCVCAT:
> > >
> > > - The concept of database "incarnations" only works if
> > > you are using an RCVCAT. We found out (the hard)
> > > way that this is a big deal. That is, if you use the
> > > controlfile instead of an RCVCAT, you won't be able
> > > to use "incarnations". A BIG DEAL
> > > - Some of the reporting is better
> > >
> > > Cons to using RCVCAT:
> > >
> > > - Increased support required (one or more additional
> > > instances to support).
> > > - If you have multiple DB's with the same DBID, each
> > > will require its own RCVCAT, which is not practical
> > > in our case.
> > >
> > > Write to me if you need more info.
> > >
> > > Bill
> > >
> > >
> > >
> > > "Gary Mandaracas" <garym_at_singnet.com.sg> wrote in message
> > > news:b2ljd4$ub7$1_at_mawar.singnet.com.sg...
> > > > Can anyone advise,
> > > >
> > > > We have installed HP's Data Protector to backup our Oracle databses
> and
> > > > other systems in two of our sites and been given different advise by
> > > > consultants working on each installation.
> > > >
> > > > For Data Protector you can configure the backup to integrate with RMAN
> or
> > > > make use of Control files. In the first install we where advised to
> > > > configure RMAN prior to the consultant coming in to install and set-up
> the
> > > > backup software, however in a more recent install at another site the
> > > > consultant advised us to make use of the Control files.
> > > >
> > > > Is he cutting corners to get the job done or does it really make no
> > > > difference? What are the pros and cons of each approach?
> > > >
> > > > Any advice would be appreciated.
> > > >
> > > > Gary
> > > >
> > > >
Received on Wed Feb 19 2003 - 11:16:48 CST