Re: Two questions

Thank you.

Helpful as ever.

"Jonathan Lewis" <jonathan_at_jlcomp.demon.co.uk> wrote in message news:998147500.16041.0.nnrp-12.9e984b29_at_news.demon.co.uk...
>
> Possibly because they are thinking in the
> context of RMAN, and rman never backs
> up the online redo logs.
>
> --
> Jonathan Lewis
>
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>
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>
>
> Keith Boulton wrote in message ...
> >I started this as a new thread to avoid giving the impression that I was
> >just continuing that argument.
> >
> >Tom Kyte very kindly put a reference to the Oracle Docs re inconsistent
> >backups which I've just read, but they don't seem to make sense to me:
> >
> >"If you run your database in NOARCHIVELOG mode, only back it up when you
> >have closed it cleanly using the IMMEDIATE or NORMAL options.
Inconsistent
> >whole database backups of databases running in NOARCHIVELOG mode are
usable
> >only if the redo logs containing the changes made prior to the backup are
> >available when you
> >restore it--an unlikely occurrence. "
> >
> >Why is this unlikely? The set of non-archived redo logs and the database
> >data files are sufficient to redo any outstanding changes - that's why we
> >can't reuse a redo log until the database checkpoint is complete. There
is
> >no need to use archived redo logs. Surely, if you were doing a cold
backup,
> >you would be backing up both the database data files and the redo logs?
> >
> >"The reason that NOARCHIVELOG inconsistent backups are not recommended is
> >that the datafile headers of the backed up files contain different SCNs
(a
> >normal shutdown guarantees the consistency of these SCNs), and because
the
> >database is in NOARCHIVELOG mode, no archived redo logs are available to
> >apply the lost changes. For this reason, RMAN does not allow you to back
up
> >a database that has been running in NOARCHIVELOG mode and shut down
> >abnormally because the backup is not usable for recovery. "
> >
> >There is *never* a need to use archived redo logs to perform instance
> >recovery after a shutdown abort, so why this statement?
> >
> >
> >
> >
> >
>
>
Received on Sat Aug 18 2001 - 10:28:13 CDT