Re: Backup Oracle, With or Without RMAN

From: Mark D Powell <>
Date: Sat, 17 Oct 2009 08:14:47 -0700 (PDT)
Message-ID: <>

On Oct 17, 9:51 am, hpuxrac <> wrote:
> On Oct 17, 3:06 am, Fabrice <> wrote:
> > Hello,
> > I'm wondering if I have to use RMAN today.
> > Sorry for my long post, but I have a "big" interrogation with rman.
> > thanks.
> > 1. For the moment, I backup my database without RMAN : but with commands of
> > the system files.
> > --> Every night the database is stopped by a shutdown immediate. All the
> > files of my production database are copied via network on a third backup
> > server (The server is in an other place).
> > I keep one week of backup set.
> > Each days my backup set is : all the datafiles, the controlfiles, the
> > redologs, the redologs archieved, init and pfile , and password file.
> > Beside that, I realize some logical export that I can imort in another
> > database. I have also a physical standby.
> > Today, If my production server crash, I tell me that I can buy a new server,
> > reinstall Oracle with the same configuration and get a set of my backup
> > from the network by copying the file in their place.
> > I'don't speak about my standby. In my mind I have always a set of all the
> > files of the production database in other place and physical cold files.
> > 2. Can I do the same thing with RMAN.
> > I'm not conformtable with it.
> > In my mind RMAN is a black hole.
> > --> If I want to realize a cold backup of my database (as in the point 1)
> > and keep all the files of my prod database in a third server, is it
> > possible ?
> > For me, it seems that RMAN backup on a local disk ? What do do you do if the
> > server is out ? In the worst scenario, can we get the files backup by RMAN
> > without RMAN and copy by commands of the system file all the files (backup
> > with rman) of the database in an other server with the same configuration.
> > Do RMAN realise a copy of the files of the database ?
> > Can we apply a full backup of a database in an another server (for example a
> > rebuild server) with an new and clean installation.
> > Example :
> > . You backup your database all the day. A full backup with RMAN.
> > --> (Where do you put the files ?)
> > . The third day, the server is out. You can't restart it.
> > . You have an another physical server.
> > . You realize a new installation of Oracle 10g.
> > . You install the same instance, same configuration, name and location for
> > the files.
> > . Now can you get the files backup with rman and put it in place to restart
> > the instance and have a database in the time of the last nigt backup.
> > For the moment I can do that with my copy of all my files.
> > Thanks for your help.
> > Fabrice
> You can certainly do good plausible useable backups without rman.  You
> can do cold backups without rman ( like you do ) and you can do hot
> backups while the database is up without rman.
> Any of the backups that one might do without rman can also be done
> with rman.
> If you have tested and documented your backup and recovery scenarios
> ( and re test them regularly ) well you are way ahead of where most
> sites are even if they are using rman.
> That being said ... rman is the way to go 98 percent of the time.
> There are however a number of the recover commands that I often run in
> sqlplus for various reasons.
> Instead of having doubts and having worries about rman why not buy the
> most recent Hart/Freeman RMAN book that is close to or at the release
> level you are running and start getting your feet wet.  You have to
> have a test system and some resources and time at your disposal.
> I for one find that having an rman based disk backup is something that
> makes me sleep better at night.  I also do have a "cold backup" of
> some critical systems that is done storage system based ( very
> quickly ) in a few minutes of weekly downtime "just in case".  ( With
> some storage systems one can get a clone ( not a snapshot ) of a large
> database pretty dang fast ... if you have the storage ... why not ? ).- Hide quoted text -
> - Show quoted text -

With 11g the Oracle Enterprise Manager relies on rman for most of the automatic diagnostic recovery feature actions. So if you are an EM shop this is one more reason to use rman for your backups.

We still use manual hot backups on most of our databases because we wrote our backups scripts long ago and have used the backups for recovery so making a change requires a lot of justification and approvals. Also we pipe our backup files into compress and untill 10g you could not compress the backups as part of the process. Advanced compression for use by rman is also an extra cost item.

Still, using rman for your backups should be given regular consideration. If you have multiple databases there is not reason you cannot switch backups methods over time as you do upgrades and new installations.

HTH -- Mark D Powell -- Received on Sat Oct 17 2009 - 10:14:47 CDT

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