RE: Question about RMAN Datafile + Archivelog Backups
Date: Wed, 2 Dec 2009 13:54:37 -0500
Message-ID: <6B0D50B70F12BD41B5A67F14F5AA887F02895DFE_at_us-bos-mx022.na.pxl.int>
Well, I hate to correct Jared, but if you use rman to backup your database it does an archive log switch for you and backups up that file as a part of the backup.
Dick Goulet
Senior Oracle DBA/NA Team Lead
PAREXEL International
From: oracle-l-bounce_at_freelists.org
[mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Mark W. Farnham
Sent: Wednesday, December 02, 2009 12:53 PM
To: jkstill_at_gmail.com; ChrisDavid.Taylor_at_ingrambarge.com
Cc: 'Oracle-L_at_freelists.org'
Subject: RE: Question about RMAN Datafile + Archivelog Backups
Jared is spot on. If you want to minimize the size of the RMAN backup + archive set, then possibly include just the archives that are required to bring the database up to the point in time a little bit after RMAN is finished with its part. Even though you don't strictly need it with RMAN, a gratuitous alter system switch logfile, waiting for that archive to complete and tossing the archives from just before the RMAN window started through that last one you switched out of is a good habit from the roll your own physical recovery protocols.
Add that to a routine backup of all the archived redo logs, preferrably an overlapping window so that every archived redo log appears on at least two independent sets of media before it is purged on line. For example if you make a copy every day of the whole thing and purge yesterday (and previous but there shouldn't be any...) then every backup set has two days worth and every archive appears on two sets.
And when you're one of the
"Quite a few DBA's not only duplex archive logs, but also
back them up twice before deleting them."
please be sure that operations knows you want them backed up as two sets on completely independent media.
Two copies on the same SAN is probably not worth the space, and two sets on the same tape is just plain silly - but that last bit took a frustratingly long time to explain more than once and at more than one shop.
mwf
never trust your career to one copy of data on spinning rust or ribbon rust. (and yes, I know its mostly not iron rust anymore.)
From: oracle-l-bounce_at_freelists.org
[mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Jared Still
<snip>
If the archive logs are not included with the backup,
there's a pretty good chance you will run into a
scenario where a restore is needed, but not all
the required archive logs are available.
Suppose the storage crashes 12 hours after the backup?
Not only would the 12 hours of work be lost because the
archive logs were not backed up, but the backup itself
would likely be useless, as the archive logs created during
the backup would not be available.
This seems a good opportunity for you to educate
folks regarding the basics of Oracle recovery so they
understand why archive logs MUST be backed up.
Quite a few DBA's not only duplex archive logs, but also
back them up twice before deleting them.
Jared Still
Certifiable <snip>
On Wed, Dec 2, 2009 at 8:56 AM, Taylor, Chris David <ChrisDavid.Taylor_at_ingrambarge.com> wrote:
What are the risks of NOT including archivelogs as part of the RMAN routine backups? I have been tasked with reducing our backup sizes and was asked if we had to include archivelogs in our backups. I realized that I didn't have a real good answer to this. My gut says to backup everything, but I cannot think of an exceptional reason to include archivelogs in my backup sets. When you have to restore you only need the archivelogs since the last backup, right? Or am I forgetting something important here? Chris Taylor<snip>
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