Re: rman restore from consistent backup
Date: Tue, 10 Feb 2009 02:10:45 -0800 (PST)
On Feb 9, 1:50 pm, hpuxrac <johnbhur..._at_sbcglobal.net> wrote:
> On Feb 9, 12:08 pm, Charles Hooper <hooperc2..._at_yahoo.com> wrote:
> > > If you are running in noarchivelog mode the only way to use rman is to
> > > take a backup when the database is shutdown ( not open ).
> > > Think about buying Robert Freeman's most recent ( 10g ) RMAN book.
> > Hpuxrac,
> > Some clarification. When you state shutdown (not open), do you mean
> > completely shut down, or just that the database is mounted?
> shutdown immediate followed by a starup mount then the RMAN backup ...
Thanks for clarifying that statement.
> > I have
> > that RMAN book by Robert Freeman. Page 27 indicates that for a
> > database in NOACHIVELOG mode, the correct way to backup the database
> > is to shut down the database, backup the files, and then restart the
> > database. Page 245 states "RMAN will not prevent you from doing a
> > tablespace or datafile backup in NOARCHIVELOG mode (as long as the
> > database is not open). However, these backups are not really all that
> > usable when the database is in NOARCHIVELOG mode (unless you back up
> > all the tablespaces and datafiles at the same time)."
> See the complete example on page 285 in Chapter 10 "Recover your
> NOARCHIVELOG Mode database" steps your thru both the backup procedure
> and recovery procedures.
That appears to be a very good walk through which was not listed in
the index at the back of the book under the topic of NOARCHIVELOG
mode, which is how I found the other references listed above. Page
286 shows the following command used to recover the noarchivelog mode
database after a restore:
RECOVER DATABASE NOREDO; I wonder if NOREDO is the key for the OP? Page 281 states this about the NOREDO parameter:
"Following this command, recover database noredo instructs RMAN to perform final recovery operations in preparation for opening the database. Since the database is in NOARCHIVELOG mode, and there are no archived redo logs to apply and the online redo logs are missing, the noredo parameter is required."
> You seem to be mixing in 2 separate things ( well at least separate
> pages ) from the author as different that are really the same. In
> NOARCHIVELOG mode using RMAN ( or not ) you really want to get all the
> database at the same time ... not some tablespaces at one point and
> others at a different point ... which you can do ( but often reaches a
> point of diminishing return ) in ARCHIVELOG mode.
Yes, I believe that is correct that I was mixing 2 separate things regarding NOARCHIVELOG mode. The first method, I believe, is describing an operating system level offline copy of the database files. The second method is describing an RMAN backup with the database mounted, but not opened. The portion of the paragraph beginning with "However" was the start of another under-developed thought in my reply, possibly serving as a potential source of the problem for the OP.
> > Contrast that advice to the advice shown here in "RMAN Recipes for
> > Oracle Database 11g" (another book that I own):http://books.google.com/books?id=qISYkSBV2hgC&pg=PA10
> > "If you're running the database in noarchivelog mode, the recommended
> > approach to backing up the database is to shut down the database
> > cleanly first and then to back up all the datafiles. If you're using
> > RMAN to perform an offline backup, the database must be mounted before
> > you can actually perform the RMAN backup. This is because RMAN needs
> > to update the target control file."
> ??? It is the same advice ... see the example from Freeman where you
> start by recovering the controlfile in nomount ... then mount ... the
> restore database ... then recover database noredo ... then alter
> database open resetlogs ... ( then take a backup immediately ).
It is the same advice, captured in a single paragraph, rather than being partially stated on several pages, as seems to happen with several topics in the "Oracle Database 10g RMAN Backup & Recovery" book.
> > To help the OP, what is the correct way to back up the database in
> > noarchivelog mode? The error reported indicates that an inconsistent
> > backup was captured. I wonder if the backup was captured after a
> > shutdown abort, or a failed shutdown immediate - see the timeout note
> > at the bottom of this page:http://download.oracle.com/docs/cd/B28359_01/server.111/b28310/start0...
> See above. For the OP ... consider implementing a procedure where you
> at least get the database in archivelog mode briefly before during
> after briefly after the RMAN backup it reduces some of the
> complexity. Better yet keep it in archivelog mode gives you much more
> flexibility with recovery scenarios.
To the OP, a final note, which Sybrand among others have repeatedly stated (and I don't think too many people would want to disagree with), from "RMAN Recipes for Oracle Database 11g" Page 7: "If you are running a production database - or if you want to make sure all the data changes made to any database, for that matter, are always protected - you must operate your database in archivelog mode."
IT Manager/Oracle DBA
K&M Machine-Fabricating, Inc. Received on Tue Feb 10 2009 - 04:10:45 CST