Re: Confusion why online redo logs should never be backed up.

Hi Jared,

How does restoring online logs from a cold backup avoid a resetlogs ? If your database has been up since the backup, any recovery that requires you to overwrite your current redo logs must require a resetlogs by definition.

The only exception to that rule is if you perform a full restore back to the time of the backup. Which probably means you don't have your database in archivelog mode else why not use the archive logs in recovery (in which case we're back to an incomplete scenario and your backup redologs are no good anyway) But if it's a complete restore scenario and you don't have the online redo logs backed up, so what ? You open the database with resetlogs and you're away. There's absolutely no need for a fresh backup because if anything goes wrong between backups, you simply perform the restore again. The scenario hasn't changed from what it was previously. The argument but what if the backups weren't performed correctly seems odd when no such argument applies to hot backups or the backup of the online redo logs etc....

Even when you perform an incomplete recovery, the requirement for a fresh backup is only optional. The database is fully protected without it and can quite happily use the subsequent redologs. The recovery process to recover through a resetlog is a little more involved but it's not *that* involved.

But I digress.

IMHO is no need to backup online redologs whether for hot or cold backups, whether for a complete or incomplete recovery.

Just ask RMAN ;)

Cheers

Richard

• Original Message ----- To: "Multiple recipients of list ORACLE-L" <ORACLE-L_at_fatcity.com> Sent: Friday, May 23, 2003 5:48 AM

> This thread will likely go on for awhile.
>
> Why not look it up in the archives at fatcity.com?
>
> That said, the statement is patently incorrect.
>
> Hot backups: no, you don't backup online logs
>
> Cold backups: yes, it's a good idea.
>
> I'll catch flames for that, but don't care. I've had to use the
> online logs restored from tape to recover a database on
> a few occasions. I was glad to have them. ( someone
> else was not shutting down the database properly )
>
> Restoring the online logs from a cold backup also allows
> you to avoid 'open resetlogs'. If you open a database with
> resetlogs, you must back it up before anyone is allowed
> to use it.
>
> Jared
>
>
>
>
>
>
> Rick_Cale_at_teamhealth.com
> Sent by: root_at_fatcity.com
> 05/22/2003 11:27 AM
> Please respond to ORACLE-L
>
>
> To: Multiple recipients of list ORACLE-L
<ORACLE-L_at_fatcity.com>
> cc:
> Subject: Confusion why online redo logs should never be
backed up.
>
>
>
> Hi All,
>
> In Oracle8i Backup & Recovery Handbook pg 13 it states "Finally, online
> redo log files should never be backed up....So, it is good practice not to
> back up online log files for ANY kind of backup.
>
> Can someone clearly explain why this is recommended?
>
> Thanks
> Rick
>
> --
> Please see the official ORACLE-L FAQ: http://www.orafaq.net
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> Author:
> INET: Rick_Cale_at_teamhealth.com
>
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-- 
Please see the official ORACLE-L FAQ: http://www.orafaq.net
-- 
Author: Richard Foote
  INET: richard.foote_at_bigpond.com

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