Re: Restoring & recovering in NOARCHIVELOG

On Fri, 25 Jul 2003 12:03:29 +0100, Norman Dunbar <Norman.Dunbar_at_lfs.co.uk> wrote:

> Morning (just) Carlos,
>
> if you are not running in ARCHIVELOG then your recovery options are
> simple - you recover to the last dump.

Not true Norman.

Recovery means replay redo -and it doesn't matter where that redo comes from. If the online logs are huge enough, then you can restore an extremely old database and play it forward just by using the online logs. The degree to which you can recover in such a scenario is limited only by the size of the online logs.

Make 'em big enough to hold a weeks' redo, and you can recover from last week's cold backup. Completely.

Not that this is a reliable way to run a business, mind you.

~QM

> This includes datafiles,
> controlfiles and on-line redolog files. This means that your redo
> information is all up to date as of the time you closed the database to
> take the dump.
>
> So, you have no chance of rolling forward/recovering the days work,
> because you won't be able (I'm certain, but untested) to startup the
> database with the redologs from today with the backups of yesterdays
> control and datafiles. (Unless a resetlogs is involved somewhere along
> the line - which will negate any possibility of recvovering from those
> logfiles.)
>
> Cheers,
> Norman.
>
> -------------------------------------
> Norman Dunbar
> Database/Unix administrator
> Lynx Financial Systems Ltd.
> mailto:Norman.Dunbar_at_LFS.co.uk
> Tel: 0113 289 6265
> Fax: 0113 289 3146
> URL: http://www.Lynx-FS.com
> -------------------------------------
>
>
> -----Original Message-----
> From: miotromailcarlos_at_netscape.net (Carlos)
> [mailto:miotromailcarlos_at_netscape.net]
> Posted At: Friday, July 25, 2003 11:26 AM
> Posted To: server
> Conversation: Restoring & recovering in NOARCHIVELOG
> Subject: Restoring & recovering in NOARCHIVELOG
>
>
> Hi all.
>
> We are working with Oracle 8.1.6 on Win NT in a production environment
> (don't blame me, It's heritage). The Database archiving mode is
> NOARCHIVELOG (again don't blame me). We do whole database backups
> daily al the end of the day (It's not a 24/7 DB). Due to requisites,
> we must be able to restore the status that the DB had at the beginning
> of the day (start) in order to reprocess (by external processes) all
> the activity of the day if necessary (this is easily done by restoring
> the last-night backup). But I'm wondering about recovering the DB if a
> HW problem occurs. Here is where my question comes out: If we use redo
> log files large enough to hold all the redo activities of a whole day
> we could not only restore the 'last-night cold backup' in order to
> reprocess, but recover the DB status to the instant before a HW
> failure as well by using the redo log files to roll forward.
> Am I right?
>
> Thanks in advance.
>
> Carlos.
>
>

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