Re: backup and recovery procedures / resetlog

On Tue, 02 Jul 2002 21:22:12 +0200, Bruno Jargot <see_at_reply.to.invalid> wrote:

>I'm currently writing procedures for the backup and recovery of
>databases.
>
>I read carefully the excellent paper of Howard J. Rogers but I've some
>questions.
>
>1- Before doing a incomplete recovery, Howard strongly recommends a
>backup in order to be able to redo the recovery if necessary.
>
>I don't understand why I could not redo the recovery.
>
>I've a backup control file (trace) with each backup. If I want to redo
>the recovery, I should be able to use the backup control file and play
>again each archivelog until the resetlog. No ?
>If I do a backup of only the redolog files before the resetlog, I
>should have no loss. No ?
>
>If I don't backup the Control Files before the resetlogs, what are the
>consequence for a incomplete recovery (except the need of using the
>backup controlfiles) ?
>
>2- After a resetlog, Howard recommends to do a *cold* backup. A hot
>backup is not sufficient ? Why ?
>
>
>Thank you very much in advance for you advices,

1 Assume your restore fails. Need I say more. If you didn't make a backup of the current situation you've just lost everything.

2 The hot backup will be inconsistent, as every hot backup. Which is why the redologs come into play. You can't go back to before the resetlogs,NEVER. So you should want to have just that extra bit of precaution, and have noone tell you that it isn't necessary. The first law of Murphy is: Everything that can go wrong, will go wrong.
The second law of Murphy is: Murphy was an optimist.

Regards

Sybrand Bakker, Senior Oracle DBA

To reply remove -verwijderdit from my e-mail address Received on Tue Jul 02 2002 - 14:43:50 CDT