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Re: Control File Backup

From: Howard J. Rogers <howardjr_at_www.com>
Date: Sat, 3 Feb 2001 10:21:57 +1100
Message-ID: <3a7b410e$1@news.iprimus.com.au>

You don't say what is going wrong, and I'm assuming you physically aren't getting a copy of your Control File in the requisite directory, but let me tell you straight up that even if it was working, your backup would be worthless.

You can NOT take hot backups of ANYTHING in Oracle, unless you have something that can make the resulting inconsistent mess consistent once more.

Now with datafiles, we have redo. Applying redo makes inconsistent datafiles consistent. The restored files can thus be made useable, provided all required redo is applied.

What do we have that we can apply to Control Files? Er... nothing.

You therefore cannot just copy Control Files whilst the database is hot. For this reason, Oracle cunningly invented the piece of SQL syntax: 'alter database backup controlfile to 'd:\blah\blah\blah.bkp' -since this command causes Oracle itself to generate the requisite consistent image. Unless you use that command (or, preferably, it's trace file cousin), your control file backups will be unuseable when it comes to the crunch.

Regards
HJR "VA Access" <vaaccess_at_my-deja.com> wrote in message news:95f1j5$g4s$1_at_nnrp1.deja.com...
> Each night I run a process that puts the DB into hot backup mode and
> then copies the db files to a directory which is backed up a little bit
> later. Anyway, I noticed that the Control Files are not getting copied
> correctly, but all the datafile are doing just fine. So, my question
> is, why?
>
> Here's what happens:
> SQL runs that puts all the tablespaces into backup mode.
>
> Then, the copying occurs. Here's a snipit:
> PLUS33W.EXE sys/PASSWORD_at_INSTANCE
> d:\orant\bin\ocopy73 d:\orant\database\CTL1CODA.ORA d:\dba_admin\backup
> d:\orant\bin\ocopy73 d:\orant\database\LOG1CODA.ORA d:\dba_admin\backup
>
>
> Sent via Deja.com
> http://www.deja.com/
Received on Fri Feb 02 2001 - 17:21:57 CST

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