Oracle would not know about your triple mirroring. The
firmware/hardware/software supplied by your disk storage vendor will handle
it during the resilvering of the disk volumes. From what I know and
understand, one will have to put ALL tablespaces in backup mode, before
breaking the triple mirror. We do not use this method, so I can not be more
specific, but I am sure others are using method.

If anyone on the list is using this process, please share your experience.
Thanks.

Regards,

- Kirti Deshpande
Verizon Information Services
http://www.superpages.com

> -----Original Message-----
> From: [Email Address Removed] [SMTP:[Email Address Removed] Sent: Saturday, June 30, 2001 10:01 AM
> Subject: RE: tripple mirroring
>
>
> Yes I had read a few notes with that, says oracle still writes to data
> files, all it does during hot backup was to freeze scn of the data files
> belong to the hot tablespace and then update them after the tablespace is
> put off hot backup.
> This will allow oracle to know from which scn to begin recovery from.
> But my question is does tripple mirroring has any side affect in this?
> becuase once we brake the mirror, those set of files
> on the broken mirror are like static ones.
>
> thanks
>
>
>
>
>
> "Deshpande, Kirti"
>
> <kirti.[Email Address Removed] To:
> [Email Address Removed]
> rizon.com> "LazyDBA.com Discussion"
> <[Email Address Removed]
> cc:
>
> 30/06/2001 05:53 PM Subject: RE: tripple
> mirroring
>
>
>
>
>
>
>
>
> Shahid,
> It is a common misconception that Oracle does not write to files when
> those
> are in hot backup mode. A few books gives the reader this impression. But
> it
> is not true.
> Jeremiah Wilton had written an excellent note about this. I suggest you
> read
> it at http://www.speakeasy.org/~jwilton/hot-backup.html. Also, the Backup
> and Recovery Handbook by Rama Velpuri addresses this issue in great
> detail.
>
> What you are trying to do with triple mirroring (and silvering) should
> work
> fine. I still urge you that test the recovery process to make sure your
> strategy works in each Recovery scenarios.
>
> Good luck.
>
> Regards,
>
> - Kirti Deshpande
> Verizon Information Services
> http://www.superpages.com
>
> > -----Original Message-----
> > From: [Email Address Removed] [SMTP:[Email Address Removed] > Sent: Saturday, June 30, 2001 8:21 AM
> > To: LazyDBA.com Discussion
> > Subject: tripple mirroring
> >
> > during a hot backup why the data files are still being updated? I though
> > they would go on read only and all updates will route to redo logs.
> > If yes, then we are simply copying open files with possible update?
> > We were thinking of using tripple mirroring (silvering) for hot backups
> > but
> > now with this , how would the internal logic be if we break the third
> > mirror?
> >
> > Thanks
> >
> >
> > --------
> > Oracle documentation is here:
> > http://tahiti.oracle.com/pls/tahiti/tahiti.homepage
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