Re: Some one tested RESETLOGS new functionality on 10g?
- From: Tim Gorman <tim@xxxxxxxxx>
- To: Oracle-L <oracle-l@xxxxxxxxxxxxx>
- Date: Tue, 01 Mar 2005 16:45:13 -0700
No trick question, just straight-forward DBA stuff...
We have a winner!
Mark, I owe you a tall beer or a short single-malt, whenever we meet...
on 3/1/05 4:38 PM, Mark Bole at makbo@xxxxxxxxxxx wrote:
>>>> POP QUIZ: The need for a "cold" backup immediately following RESETLOGS was
>>>> one of at least two situations where a "cold" backup was "better" from a
>>>> data protection standpoint than a "hot" backup. There remains one
>>>> situation
>>>> where a "cold" backup is better (from a data-protection standpoint) than a
>>>> "hot" backup. Can anyone name that situation?
>>>>
>>>> To put it another way, what is the situation where a production DBA might
>>>> ask to halt a production application to take a "cold" backup, and not be
>>>> crazy?
>>>
> [...]
>> Anyway, since your database was closed for the PITR, a "hot" backup isn't
>> really possible there. My question was intended for the situation where
>> either choice was possible.
>>
>> Anyone? Bueller? Bueller? Anyone?
>>
>
> If this is a trick question, then the answer is: when your database is
> in NOARCHIVELOG mode, a cold backup is better from a data protection
> standpoint than a hot backup.
>
> OK, here's a guess: you lose all members of a inactive on-line redo log
> group that has not yet been archived... (at least, that's one scenario
> mentioned in the docs). Similar reasoning would apply after any
> NOLOGGING operation in a database or tablespace without FORCE LOGGING in
> effect.
>
> Although I'm not sure why in any such situation, you couldn't archive
> all the online log groups, and then take a hot (inconsistent) backup?
>
> -Mark Bole
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