Re: Periodic restart plusses and minuses?

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Noons wrote:

> Hans Forbrich <news.hans_at_telus.net> wrote in message
news:<KDK8d.32806$N%.31956_at_edtnps84>...

>> One of the local DBAs has his heart set on nightly shutdowns to do cold
>> backups.  Another DBA wants to go for online backups.  (Archive logging is
>> up and active.)

> Ay!...... been there, done that.

>> The debate has gone all over silly territory and back and is now at: 
>> "Shutting down the database will waste all the automatic tuning benefits
>> achieved from the system finding stability in the cache, etc..  It can take
>> hours, even months to get the system stable."

> Gross exageration, the "months" thing. IMHO. Never ever saw
> such a case. It either is a very weird load system or someone
> is on vapours...

>> Does anyone have pointers to documents, white papers, books, web sites,
>> metalink note, etc. that I can drop on their desks to move them off this
>> 'shutdown detunes the database' discussion?   

> I don't think you'll find anything in that area, but...

>> 
>> (Once they're over this, I hope the discussion can get back to a pure
>> business benefits discussion!)
>> 

> Weeeeelll, is it worth even letting it move away from the business
> benefits?

> My point is: cold backups vs hot backups is a decision that should
> be based only on business requirements: does the business require
> 24X7 operation? If yes, then hot backups is the only option.
> If not then cold backups (if there is enough window) are
> an equaly valid option.

> My personal choice would be RMAN, but in Windows that may
> pose some minor problems. At least I've had some in the past.
> Mostly due to my lack of deep knowledge about it in that environment.

> Cold backups is a good one in that environment. Particularly if
> hardware assisted: shadow volumes, yadda yadda.
> I hate to use the old chestnut. So I'll just say
> it is highly contingent on the business requirements
> and pretty much little else...

The business requirements and available backup resources are the key here.  A cold backup offers the advantage over a hot backup of being a consistent point in time recovery all by itself if the forward recovery runs into an issue accessing the archived redo logs. However, if the archived redo logs are being written to a separate disk from the database files and online logs then the only real risk involved with forward recovery is running into redo log corruption.

I would suggest using hot backups throught the week and perhaps making a cold backup over the weekend if time permitted.

IMHO -- Mark D Powell --

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