Re: RMAN duplicate only used blocks?

From: Niall Litchfield <>
Date: Tue, 28 Jun 2011 17:32:27 +0100
Message-ID: <>

The source of the quote was likely the nfs clonedb feature introduced in 11g (maybe R2). Kevin Closson has an intro at it
is a cool feature, but probably won't help Alan.

On Tue, Jun 28, 2011 at 5:17 PM, <> wrote:

> I don’t believe there is any such feature. Notice the words “I believe”
> J****
> What I believe is available in 11G is that RMAN is capable of backing up
> only used blocks****
> But in 1 iTB file if only 200M is used then my understanding will be that
> somehow magically the output file will still be 1TB even though only 200MB
> was backed up.****
> Of course I have not tested it yet.****
> ** **
> Thanks ****
> ** **
> ------------------------------
> *From:* [mailto:
>] *On Behalf Of *Guillermo Alan Bort
> *Sent:* Tuesday, June 28, 2011 11:51 AM
> *To:* oracle-l-freelists
> *Subject:* RMAN duplicate only used blocks?****
> ** **
> So, the situation is this, I have a tablespace with about 600GB of free
> space (spread out in about 80 datafiles). The entire database itself has
> about 2TB and we need to copy it to another server. The problem is that we
> have 1.5TB allocated in the ASM instance in the destination server. We
> wanted to use RMAN, but the database won't fit. We could use export/import
> but it would take too long and we don't have anywhere to store the export.
> Someone pointed to me that RMAN was capable of duplicating only the used
> blocks... I researched a lot but I couldn't find it... so I'm either looking
> in the wrong place or that someone was wrong. (there is also the possibility
> that I'm very sleepy).
> I know rman can compress backups and that it only backs up used blocks
> (when doing a backupset anyway) but I think duplicate just... duplicates...
> I don't think it resizes and moves stuff around.
> Anyway... I think we will have to go with datapump for this one (we are on
> 11g anyway), but I was just wondering if I was missing a key feature in
> rman...
> thanks
> Alan.-****
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Niall Litchfield
Oracle DBA

Received on Tue Jun 28 2011 - 11:32:27 CDT

Original text of this message