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RE: RAC cold backup - alternative

From: Mark W. Farnham <>
Date: Tue, 21 Jun 2005 12:44:46 -0400
Message-ID: <>

Okay, so IF you're doing pulse updates, presumably you slug in a day's or week's worth of data. Then you possibly rebuild some aggregates or do summarizations on the newly arrived time based data, possibly update your statistics and get ready to hand the datawarehouse over to the users for a reporting window, but you want a backup before you turn them loose. You don't want to archive the big pulse update because you figure you could just apply the cycle to the previous cold backup if the wheels fall off. You don't want to endure the overhead of archiving the massive periodic update.

*THIS IS NOT AN ANALYSIS OF WHETHER THIS IS A GOOD STRATEGY, NOR AN ENDORSEMENT OF THIS STRATEGY. I'm just telling you the environment I'm presuming leading up to the following:

IF you're in that usual mode for data warehouses, then you have protracted periods where you're only reporting and not generating much redo anyway. So AFTER all the massive updates are in, switch to archivelog mode, do a hot backup any which way you want, being sure to cycle out that last redo log to archive that might be needed to create a coherent recovery set, and then flip archivelog mode off. Actually you might want to leave archiving on until just before you enter the period of mass updates, since there will be little or nothing new, but that is up to you and your perception of archivelog mode overhead during your reporting window.

Figuring out the ins and outs of making this airtight with your particular backup/recovery methodology is up to you, but you can definitely make it work with at least several different methods of backup. I realize this is not exactly what you asked, but I'd bet a dozen crullers (in a legal jurisdiction for such wagers) that is what you want to do. Oh - and your users get access sooner this way, too.



-----Original Message-----

[]On Behalf Of Steiner, Randy Sent: Tuesday, June 21, 2005 9:01 AM
Subject: RAC cold backup

Is anyone doing a cold backup on a grid? If so, how are you shutting down the database in the rman script? Putting Shutdown in the script only stops one instance. The best I can come up with is to run srvctl stop database before the script.

I have a data warehouse with no archive logs, so an online backup is out.



-- Received on Tue Jun 21 2005 - 12:53:12 CDT

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