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

From: Richard Foote <>
Date: Sun, 25 May 2003 04:56:38 -0800
Message-ID: <>

> Richard,
> You must have missed one. :)

Hi Jared,

I think we're going to have to introduce quotas, no more than two contributions per thread ;)

> There have been 2 occasions where someone has
> sent me 200 gb worth of database on tape, and
> the database had not been shutdown properly.
> Since the system datafile needed recovery from
> the online logs, I was very glad to have them.

I guess my point is that making a backup without shutting down the system properly is a sin akin to scratching a rare David Bowie LP, ie. somewhat unforgivable (although I admit the second sin is far worse). Make a consistent backup and/or have the database in archivelog mode, you then don't require the online redo logs ....

> I have encountered this on a very few other
> occasions, but can't recall the circumstances
> of those events.
> They are also useful when cloning a DB (without RMAN),
> though not required. Depends on how the clone
> will be used.

I guess my point here is the "though not required" bit. It simplifies the process I agree but even in this case, the online logs are not strictly required.

> As with many things, this is not a black and white
> issue. There are shades of gray. While it certainly
> not necesssary to normally backup the online logs
> during a cold backup, it is incorrect to say that
> they are never useful.

I guess we're going to have to agree to disagree. However, getting back to the subject of sins, including online redo logs in a cold backup is not really an issue that would cause me loss of sleep (unlike scratching DB LPs). Like, it doesn't really hurt. But if someone were to accidentally incorrectly restore them in a recovery scenario, ouch, that would be a sin worth having a chat about ;)



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Author: Richard Foote

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Received on Sun May 25 2003 - 07:56:38 CDT

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