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RE: FW: backing up rman catalog for disaster recovery

From: Marquez, Chris <>
Date: Thu, 26 May 2005 10:16:52 -0400
Message-ID: <B30C2483766F9342B6AEF108833CC84E0450BBD9@ecogenemld50.Org.Collegeboard.local>

I found these (see below) in my personal RMAN notes. While my immediate comments (below) about "CONFIGURE CONTROLFILE AUTOBACKUP" might be misguided (based on what I believe you are saying) the bug issue (below that) was very real for me at the time we first when to 9i.

Here is one more thing (is a personal problem not a technical one.) I hate 9i "CONFIGURE" parameters...if I use them I *ALWAYS* re-set them 1st thing with *ALL* of my RMAN (shell) scripts. "But they are *persistent"...yes....but I'm a well trained paranoid DBA...I assume that between backsup the Evil Empire will log into my database and change my *persistent* "CONFIGURE" parameters and thus my backup will be different, missing stuff. Again I said it was a personal problem not a technical one...but nobody ever changes anything in a database, right? :0|

Having said that you have given me new hope and I again will try the "CONFIGURE CONTROLFILE AUTOBACKUP"...along *with* my tried-and-true "copy controlfile" syntax...It never hurts to have more backup controlfiles. ;o)


Chris Marquez
Oracle DBA

>> I do not use this, but will look at my notes to see if I tested it.
>> This statement concerns me;
>> "a manually backed-up controlfile cannot be automatically restored."
>> This implies that a "CONTROLFILE AUTOBACKUP" can be automatically restored...but I disagree, about the usefulness of that..or the reality of that.
>> Again, using the RMAN rule (really all backup software rule), if I don't "Backup Meta Data", how can I restore anything!?
>> And if I do have a current controlfile ("Backup Meta Data") that can automatically restore my "CONTROLFILE AUTOBACKUP", that means the current controlfile is more current than the controlfile I will restore!...why do that?
>> The only way I see that CONTROLFILE AUTOBACKUPs might be useful is if it is a separate and identifiable RMAN file (set). Meaning I *might* be able to pick it out from a list of other RMAN backup files (sets. Then it can use it by RMAN to "replicate" or OS to "cp" it back as my database controlfile(s)).
>> Even still this controlfile backup would not be aware of subsequent archive log backups.



If you have RMAN backups that include the SPFILE, and you do either REPORT OBSOLETE or DELETE OBSOLETE with RMAN, then RMAN might incorrectly report or delete certain backups as obsolete, even if they weren't.
  1. Don't use the SPFILE ..instead use the init.ora parameter file
  2. Include in your scripts... RMAN> backup current controlfile; This will add the controlfile in a different piece handle that the autobackup command.
  3. Don't use the autobackup command. (set OFF)
    Fixed in: and 10i

# Configure RMAN to back up the control file after each backup. CONFIGURE CONTROLFILE AUTOBACKUP ON; # Configure RMAN to write controlfile autobackups to the /backup directory. CONFIGURE CONTROLFILE AUTOBACKUP FORMAT FOR DEVICE TYPE DISK TO '/backup/ora_cf%F'; -----Original Message-----
From: on behalf of Marquez, Chris Sent: Thu 5/26/2005 9:43 AM
To:; ORACLE-L Subject: RE: FW: backing up rman catalog for disaster recovery  

Good to know and I believe I have heard something of this. Could you provide the snip of RMAN syntax that would generate the "controlfile autobackup" or is it one of the 9i "CONFIGURE" parameters? Is the "controlfile autobackup" allways generated as the *last* backup object int the RMAN session?

Also, what does one of these files looks like. I often suspect that I have a (auto created) backup controlfile, but I all of my backsets use the same formant...not able to differentiate then much other than size?

>>RMAN> restore controfilefile from '<name of autobackup file>';

So I can remover *all* of my controlfiles, startup nomount with the correct init.ora file and run this command and get my controlfile back...pushed into the right place(s) as identified in my init.ora...similar/same idea as the RMAN "replicate controlfile" command syntax?...Or I could simple "$>cp..." it to my correct controlfile location and names?


Chris Marquez
Oracle DBA

-----Original Message-----
From: on behalf of Charlotte Hammond Sent: Thu 5/26/2005 6:02 AM
Subject: RE: FW: backing up rman catalog for disaster recovery  

I agree that an RMAN scripted backup controlfile is not useful, but configuring RMAN controlfile autobackup does help:

  1. You then don't have to include a copy command (internal or external) for you controlfile as RMAN does it for you automatically.
  2. The filename of the autobackup contains both the date and the database ID in a human readable format.

To get your controlfile back (without needing a catalog) you just need to do

RMAN> restore controfilefile from '<name of autobackup file>';


>>I just cheated and backed up the control file separately

"Cheat" nothing this is just smart...or reality :o|

>> run {allocate channel c4 type disk; copy current controlfile to...

>> in my shell script *every* time and AT THE END OF EACH BACKUP

>> NOT an RMAN *backup* of my controlfile (totally useless),

>> but rather a *COPY* of my controlfile.

>> Meaning it can be used without RMAN;
As I said in an earlier post, RMAN backup controlfile (IMHO) is rather useless. It is the classic "chicken and egg". You have a controlfile in the RMAN backup, but you need a current controlfile to get to the backup! (in the absence of a recover catalog). If I have a current controlfile then why do I need the one *in* the backup? Oracle should update the RMAN documentation it indicate thsi mental puzzle. Seems everyone learns this the hard way during testing...or the really hard way during a disaster. Anyone want to guess... What would be of some use when all current controlfiles and datafiles are lost and you have >1 good RMAN backups? (A worst case senario). Chris Marquez Oracle DBA -----Original Message----- From: on behalf of Dennis Williams Sent: Wed 5/25/2005 6:15 PM To: Cc: oracle-l Subject: Re: FW: backing up rman catalog for disaster recovery Actually, RMAN always writes to the control file before it updates the catalog. So even if you do an RMAN backup using a catalog, you can still recover the database using only the controlfile. Now, in Oracle8i I had problems recovering the control file from the RMAN backup, so I just cheated and backed up the control file separately after the RMAN backup completed, and made sure the control file backup was on the same tape as the RMAN backup. I have performed many recoveries using this method. Dennis Williams On 5/25/05, Ruth Gramolini <> wrote: >=20 >=20 > One very easy way is to do an rman backup with the nocatalog option. Thi= s > will use controlfile info for restores and recoveries. You can use all t= he > options of rman, just no catalog. That is what we do. >=20 > Just my $0.02, > Ruth >=20 > -----Original Message----- > From: > [] > Sent: Wednesday, May 25, 2005 4:49 AM > To:;; >; > Subject: RE: backing up rman catalog for disaster recovery >=20 >=20 > I am setting up a disaster recovery site and I was thinking about the > best way to do this. >=20 > My theory is that I would like to not just use another recovery catalog > on the DR site to backup my primary catalog but to somehow keep these > catalogs constantly in-synch so when I do need to do complete recovery > and only have the secondary rman catalog available - I wouldn't have to > recover the catalog as all of the previous backups would be found there. >=20 > So....should I do this using Oracle Data Guard on my disaster recovery > site catalog or backup rman then restore as my first procedure? Any > advice? >=20 > -- > > -- -- --------------------------------- Discover Yahoo! Get on-the-go sports scores, stock quotes, news & more. Check it out! -- -- --
Received on Thu May 26 2005 - 10:24:18 CDT

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