RE: Standby abuse

From: Goulet, Richard <Richard.Goulet_at_parexel.com>
Date: Mon, 10 Nov 2008 15:20:22 -0500
Message-ID: <23C4836D8E9C5F4280A66C0C247BC16F1FA1C115@US-BOS-MX011.na.pxl.int>


Dominic,  

    Yes you can backup the logical separately from the physical, and you should if it's being used for production purposes as it may well have to be restored someday (we always hope not, but Murphy does rule). It's just that you can't use that backup to restore the production database. Now a physical standby does allow you to do that, quickly, easily, and while offloading that task from the production server.  

Dick Goulet
Senior Oracle DBA
PAREXEL International
978.313.3426
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From: oracle-l-bounce_at_freelists.org
[mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Dominic Delmolino Sent: Monday, November 10, 2008 3:07 PM
To: Goulet, Richard
Cc: Oracle-L Freelists
Subject: Re: Standby abuse

Dick,

But that's only if I used RMAN to backup the Logical Standby and recover the Primary from those backups, right? Surely I can use RMAN to backup and recover the Standby itself, can't I?

I understand that attempting to recover the Primary database using backups of the Logical Standby won't work. Scenarios requiring recovery of the Primary would require failover and rebuild (which I understand would be extensive / expensive).

On Mon, Nov 10, 2008 at 1:45 PM, Goulet, Richard <Richard.Goulet_at_parexel.com> wrote:

        Dominic,          

            Well, you might be able to off load your backups to your logical standby if your backup method was export/import or Data Pump. But for a rman or tape backup you could not because those items are referenced elsewhere in the database and if they got out of sync your in serious trouble. As in an index entry would be pointing to a bad rowid.          

	Dick Goulet 
	Senior Oracle DBA 
	PAREXEL International 
	978.313.3426 
	 information transmitted in this communication is intended only
for the person or entity to which it is addressed and may contain confidential and/or privileged material. Any review, retransmission, dissemination or other use of, or taking of any action in reliance upon, this information by persons or entities other than the intended recipient is prohibited. If you received this in error, please destroy any copies, contact the sender and delete the material from any computer.                            

        From: ddelmoli_at_gmail.com [mailto:ddelmoli_at_gmail.com] On Behalf Of Dominic Delmolino

	Sent: Friday, November 07, 2008 5:52 PM
	To: Goulet, Richard
	Cc: Oracle-L Freelists
	Subject: Re: Standby abuse
	
	
	Dick,
	
	I'd argue that I could definitely off-load my backup needs if I
only cared about the data, and not so much of the physical aspects of how it's laid out. I generally don't like to use ROWIDs as data values since they can change, and I can't think of a reason why I'd care if the object id's were different -- can you give me an example?                  

        On Fri, Nov 7, 2008 at 4:10 PM, Goulet, Richard <Richard.Goulet_at_parexel.com> wrote:         

                Dominic,                  

                    You can't use a logical standby to off load your backup needs. This is because a logical does not replicate the original database, but only the transactions therein. Rowid's and object id's between the two will be different so you can't just move a data file from your logical standby to the primary for recovery purposes. A physical standby is the only way to do that since it does maintain rowid's and the like.                  

		Dick Goulet 
		Senior Oracle DBA 
		PAREXEL International 
		978.313.3426 
		 information transmitted in this communication is
intended only for the person or entity to which it is addressed and may contain confidential and/or privileged material. Any review, retransmission, dissemination or other use of, or taking of any action in reliance upon, this information by persons or entities other than the intended recipient is prohibited. If you received this in error, please destroy any copies, contact the sender and delete the material from any computer.                  
	-- 
	Dominic Delmolino
	




-- 
Dominic Delmolino


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Received on Mon Nov 10 2008 - 14:20:22 CST

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