Re: RMAN

On Aug 28, 9:07 am, artme..._at_yahoo.com wrote:
> On Aug 28, 5:36 am, Cristian Cudizio <cristian.cudi..._at_yahoo.it>
> wrote:
>
>
>
>
>
> > On 27 Ago, 20:19, artme..._at_yahoo.com wrote:
>
> > > Hi,
>
> > > We're setting up RMAN and configuring our environment.  We are on
> > > Oracle 10gR2.  I'm having trouble understand these commands:
>
> > > CONFIGURE DEVICE TYPE DISK BACKUP TYPE TO COMPRESSED BACKUPSET
> > > PARALLELISM 20;
> > > CONFIGURE CHANNEL DEVICE TYPE DISK FORMAT '/disk1/ora_df%t_s%s_s%p';
>
> > > They both specify disk.  But, can they be combined into one command?
> > > The documentation is really not specific on this.  They show different
> > > variants of the above, but I did not find anything on a combination of
> > > the commands.  If we can do it in one command, it makes more
> > > sense......
>
> > > Thank you.
>
> > If you seehttp://download.oracle.com/docs/cd/B19306_01/backup.102/b14194/rcmsyn...
> > you can configure different formats for different channels (for
> > different backup pieces and one backupset)
> > while "parallelism" and "compressed backupset" are "global" settings
> > for a backup set
> > you can configure different settings for different channells that
> > write different backup sets.
> > Hope this helps.
>
> > Regards,
> >  Cristian Cudizio
>
> >http://cristiancudizio.wordpress.com
>
> You know, I read someplace that it is good to put each datafile in its
> own backup piece.  Their reason was that when performing partial
> restore the files are smaller to read and the restore will be quicker.
>
> Is there any truth to this?

I almost posted this, but held my tongue because of all the sitespecific  permutations possible. It's true for me, I limit the files to 4, and the size of my datafiles to 2G. It can be particularly true if you are searching for certain archived logs among many, but that's a whole 'nother kettle of worms. I originally limited the files to 7, but in a version long ago that gave PGA issues, so went to 4. (I'm reconsidering this as I convert to 10g, and haven't really settled on an exact configuration yet.)

Also see the Oracle® Database Backup and Recovery Advanced User's Guide section about tuning RMAN performance, large_pool_size made a big difference for me, at least in earlier versions on my configuration, and I've kept it for 10g.

Hardware and OS does make a difference in these things.

jg

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