Re: exp and archive available.... recover table

From: Alexander Skwar <alexander_at_skwar.name>
Date: Fri, 13 Jul 2007 13:28:16 +0200
Message-ID: <1913877.LBYvgXfURH@kn.gn.rtr.message-center.info>

Preston <dontwantany_at_nowhere.invalid> wrote:
> Alexander Skwar wrote:

>> Preston <dontwantany_at_nowhere.invalid> wrote:

>> I now "played" a bit and am (again G) not so convinced that RMAN would
>> be my best solution. What advantage does RMAN offer over backing up
>> the "hot" database .dbf files in combination with the archived redo
>> log files?  I'm only interested in doing backup to disk. At least for
>> now.

>
> To do a hot backup, you need to put the tablespace in backup mode.

What would happen, if I would NOT do this?

I did some (probably incomplete) test, and when I tried to startup the database with still "hot" .dbf files (files which I copied while the database was completely open and usable and not in backup mode), Oracle prompted me to do a media recovery for certain datafiles.

> While it's in backup mode, any activity will result in the writing of
> the complete changed blocks, plus the changes themselves, to redo. This
> doesn't happen with RMAN, so there's less overhead. It doesn't sound
> like that would be much of a concern for you though, given that the
> database isn't normally being used when you do the backups.

You're right.

>> I guess the advantage in RMAN would be, that I could do everything
>> (restore & recover) from one interface. And, if configured properly, I
>> also could control backup to/restore from tape.

>
> To be honest I can't really see any reason for you /not/ to use RMAN,
> in conjunction with weekly cold backups. It's the 'correct' way to do
> it, & the best way if you do the vault backup first & use PIT when
> required.

While we're at being honest: As I now got my head around backing up "too much" and doing only a PIT recovery to "some" time before the backup started, I also begin to not see a reason in not using RMAN. Ehrm. Made that sense? :) I wanted to say, that RMAN begins to look good for me as well.

I'm already so far, as to say that it's not necessary to shutdown app (& Oracle) anymore. For right now, I still think that RMAN would make things (a bit) more complex. What I'm thinking about doing is to put the tablespaces in BACKUP mode, create snapshots, end BACKUP mode, backup snapshots and remove snapshots. The advantage that I see, is that recovery is easy: I'd simply do a full restore and I'd be all set, as I'd then have all the files already in the correct locations.

What am I missing again?

As you might have noticed, I'm not opposing the use of RMAN (I never was), I just need to start thinking in the "right" direction and get used to some new ideas. I'll get there ;)

Alexander Skwar Received on Fri Jul 13 2007 - 06:28:16 CDT