RE: BIG database backup methods

From: DENNIS WILLIAMS <DWILLIAMS_at_LIFETOUCH.COM>
Date: Tue, 21 Sep 2004 13:54:45 -0500
Message-ID: <0186754BC82DD511B5C600B0D0AAC4D611151B95@EXCHMN3>

Michael - Just to add one more note to what Robert said. Often RAID5 is used for extremely large databases. Since RAID5 writes slooowly, your recovery time may be even longer than you think.

Dennis Williams
DBA
Lifetouch, Inc.

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

From: oracle-l-bounce_at_freelists.org [mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Freeman Robert - IL
Sent: Tuesday, September 21, 2004 1:29 PM To: 'Kline.Michael '; 'oracle-l_at_freelists.org ' Subject: RE: BIG database backup methods

There are a few options depending on your environemnt. Incremental backups with RMAN can certainly reduce the size of your backup sets. Still, the initial full backup is going to take some time to complete. How many tape drives do you currently have access to? How long will it take to backup your 1-2 TB database to these drives? RMAN can parallelize the backup to many drives, of course.

Also, compression can help as well. Early RMAN offers a quazi compression, but 10g offers full blown compression (ala ZIP) which is most useful unless the backup is getting compressed already (i.e. Your tape system does compression).

I'm not sure about the data you have, but if you make your tablespaces read only, then you only need to back them up once (and retain that backup of couse).

Make sure management understands that recovery times will be impacted by moving from disk to tape.

If you are new to RMAN check out my Oracle Press book, Oracle9i RMAN Backup and Recovery.

Cheers!

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

From: oracle-l-bounce_at_freelists.org
To: oracle-l_at_freelists.org
Sent: 9/21/2004 1:11 PM
Subject: BIG database backup methods

We have the "luxury?" of being able to do shadow copies for many of our data warehouses. These are only in the 1-2 TB range, but with shadow copy, we start at perhaps 2AM with the syncing, and then around 4PM we stop the database, wait about 5 minutes, break the volumes and we're back up.

Management is getting very hungry looking at all these disks that are for backup and thinking "If we used RMAN and went to tape it would be better...

I'm not so sure. 1-2 TB in 5 minutes is pretty good.

What are others doing?

Michael Kline
Database Administration
SunTrust Technology Center
1030 Wilmer Avenue
Richmond, Virginia 23227
Outside 804.261.9446
STNet 643.9446

Cell 804.744.1545
<mailto:michael.kline_at_suntrust.com> michael.kline_at_suntrust.com

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http://www.freelists.org/webpage/oracle-l Received on Tue Sep 21 2004 - 13:52:11 CDT