Re: Which control file should be used to do recovery?

1. Yes you can use the control file copied as part of the cold backup. You can use the syntax recover database using backup controlfile. But you have to open the database with 'RESETLOGS'. Then you have to do cold backup immediately.

You can not use a control file which was copied while the database is running. But after the crash, you can use the current controlfile if it is not lost. Best approach is to mirror the control file onto 3 different disks and hope that atleast one of them survives the crash. Then you can use that controlfile to do the recovery. You need to go to backup controlfile only if you lost all the controlfiles and you donot the structure of the database. If you know the structure of the database then you can try to create a controlfile using 'CREATE CONTROLFILE' statement and use it do the recovery. In order to create the control file you should startup nomount.

raghuvir

In article <7fqjr0$gcv$1_at_nnrp1.dejanews.com>   gmei_at_my-dejanews.com wrote:
> Hi, oracle gurus:
>
> I have a couple of questions about oracle db backup and recovery.
>
> We have an oracle database (8.0.5) running in archivelog mode on a unix
> machine. Every night we backup archived log files to another unix box. And
> every weekend we do a cold backup. As an example, say
>
> on 4/17/99 (Sat), we do a cold backup by doing: 1.shutdown the db, 2. OS copy
> all datafile, control file, init.ora file and on-line redo log file. 3. start
> database 4. do a full database export
>
> Then on each night, we only copy archived redo log files (not backing control
> file every night).
>
> Assuming we have not done any "structure change" to the db (not dropping or
> adding tabelspace, renaming datafile), and on 4/22/99, we had a db crash and
> db was corrupted. We want to do db recorvey starting from 4/17/99's cold
> back.
>
> So, my questions are:
>
> 1. Should I use 4/17/99's control file, or should I use 4/22/99's control file
> to do recovery?
> I think I can use 4/17/99's control file and do something like:
>
> RECOVER DATABASE USING BACKUP CONTROLFILE;
>
> Is this correct?
>
> 2. I notice even without "structure change", the control file keeps
> changing. I made serveral copies of control file at different point of time
> and use unix "diff" to see if there is any change. If the control file keeps
> changing, could I use old cold control file to do recovery or should I backup
> control file every day?
>
> If you reply, please send a copy to zlmei_at_hotmail.com
>
> Thanks in advance.
>
> Guang
>
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-----------== Posted via Deja News, The Discussion Network ==---------- http://www.dejanews.com/ Search, Read, Discuss, or Start Your Own Received on Sat Apr 24 1999 - 22:17:22 CDT