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RE: [oracle-l] A few rman questions

From: DENNIS WILLIAMS <DWILLIAMS_at_LIFETOUCH.COM>
Date: Wed, 28 Jan 2004 11:26:39 -0600
Message-ID: <0186754BC82DD511B5C600B0D0AAC4D607AFFE1B@EXCHMN3>


Dan

   Yes, Freeman has an entire appendix devoted to the differences with 8i. Given the time it could save you, I think the book price is a no-brainer.

   Yes, I'm talking about issuing the alter database backup controlfile to . . .

   Perhaps I should explain a little more about my disaster recovery test. My mandate from management was: "Pretend the computer room is no longer available to you. All you have is whatever was written to the backup tape. Pretend you have another computer, and your task is to prove that you can recover our valuable data given just what is on the backup tape." In other words, this new RMAN may be really keen, but how could we trust it if the chips were down? That is why I found it convenient to have a current copy of the control file on that backup tape to get the whole process started. Also, I did this on Oracle 8.1.6 and 8.1.7 may have some improvements in terms of extracting the control file from the RMAN backup set.

Dennis Williams
DBA
Lifetouch, Inc.
dwilliams_at_lifetouch.com

-----Original Message-----
From: Daniel Hanks [mailto:hanksdc_at_about-inc.com] Sent: Wednesday, January 28, 2004 10:44 AM To: 'oracle-l_at_freelists.org'
Subject: RE: [oracle-l] A few rman questions

On Wed, 28 Jan 2004, DENNIS WILLIAMS wrote:

> Dan
> I very much agree with Ruth that you should get Robert's book. I would
> say that he provides a number of best practices.
> Speaking of best practices, I've got one for you that isn't specific to
> RMAN. Regardless of your backup method, test your backup configuration
> periodically. Don't trust an untested backup method.

Thankfully, I've got some machines available to do just that.

> You don't say which Oracle version you are on. That makes a lot of
> difference with RMAN.

8.1.7

> Robert discusses copies quite a bit. One thing he points out is that
with
> the copy command you must name specific files. Since our main reason for
> using RMAN was to get incremental backups working, I didn't see what copy
> would do for me.
> For controlfiles, in 8i I had difficulty getting RMAN to cough up the
> control file from the backup set (RMAN wouldn't work if the instance
wasn't
> mounted, but you can't mount the database unless you have a control file),
> so I back the control file up after the RMAN backup by having RMAN issue
the
> SQL command. Others on this list report their success on this issue. I

Just so we're on the same page, I take it you mean 'alter database backup controlfile to ...'? I can see the benefit in this case of having a 'regular' copy of the controlfile backed up somewhere. But that begs the question, supposedly the rman 'copy' command does just that--make a regular copy of the controlfile that can be used without any further processing in recovery operations. Is there any real difference between an rman 'copy' of the controlfile, and an 'alter database backup controlfile to ...'?

> understand 9i is much better in this respect, but I haven't had the
> opportunity to test it.
>
> Dennis Williams
> DBA
> Lifetouch, Inc.
> dwilliams_at_lifetouch.com
>

Thanks for your response, I much appreciate it!

> -----Original Message-----
> From: Ruth Gramolini [mailto:rgramolini_at_tax.state.vt.us]
> Sent: Wednesday, January 28, 2004 7:15 AM
> To: oracle-l_at_freelists.org
> Subject: RE: [oracle-l] A few rman questions
>
>
> Dan,
>
> Robert Freeman has written a great rman book but I think the best place to
> start is with the Backup and Recovery Manual which is part of the Oracle
> documentation. In order to do point in time or complete recovery you need
> to have rman backups and controlfile backups. You can set up you rman
> configuration files to to autocontrolfile backups at the end of every
backup
> and this will make a copy of your controlifle to a place you specify as
the
> last step as well as the normal backup of the controlfile which is
contained
> in a level 0 rman backup. With this feature, the controlfile which has
the
> necessary info can be restored. Have a look at rman configurations in the
> docs.
>
> Good luck,
> Ruth
>
> -----Original Message-----
> From: oracle-l-bounce_at_freelists.org
> [mailto:oracle-l-bounce_at_freelists.org]On Behalf Of Daniel Hanks
> Sent: Tuesday, January 27, 2004 4:59 PM
> To: oracle-l_at_freelists.org
> Subject: [oracle-l] A few rman questions
>
>
> I'm in the process of revamping our backup system (which is
> mostly inherited from another DBA), and had a few questions about
> rman I've come across as I review the system.
>
> 1) 'copy' vs. 'backup'. In our current setup, we use the 'backup'
> rman command to handle the datafiles, and the archive logs, but
> 'copy' is used to backup the controlfile. The Oracle
> documentation says this:
>
> "In many cases, copying datafiles is more beneficial than backing
> them up, since the output is suitable for use without any
> additional processing. In contrast, you must process a backup set
> with a restore command before it is usable. So, you can perform
> media recovery on a datafile copy, but not directly on a backup
> set, even if it backs up only one datafile and contains a single
> backup piece."
>
> So am I better off just leaving the controlfiles (since they're
> small) handled by 'copy' instead of 'backup'? Is having to
> process a backup set containing one controlfile with a 'restore'
> command that much of an issue? Maybe making a backup set of a
> single controlfile is overkill?
>
> 2) Are there any "Best practices" documents with respect to rman
> that list members would recommend?
>
> Thanks again for your helpful comments,
>
> -- Dan
> ========================================================================
> Daniel Hanks - Systems/Database Administrator
> About Inc., Web Services Division
> ========================================================================
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   About Inc., Web Services Division
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Received on Wed Jan 28 2004 - 11:26:39 CST

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