Re: datafiles and tempfiles

Chuck wrote:

> The database is no noarchivelog mode and is not a production database.
>
> "Daniel Morgan" <dmorgan_at_exesolutions.com> wrote in message
> news:3D220325.ED7967FD_at_exesolutions.com...
> > Sean M wrote:
> >
> > > Chuck wrote:
> > > >
> > > > Yes I back up online logs too. I do it for two reasons
> > > >
> > > > 1. It simplifies the restore script. I just run a tar -xvf filename
> and I am
> > > > done. No additional steps of resetting logs or recreating tablespaces
> after
> > > > restarting the database.
> > >
> > > Are you running in archivelog mode? If so, Oracle does NOT recommend
> > > backing up your online redo logs, hot or cold. I would argue that you
> > > should not get in the habit of backing up online redo logs regardless of
> > > whether you are in archivelog mode or not. You NEVER require backups of
> > > them for recovery, and the habit can seriously burn you if your database
> > > is in archivelog mode.
> > >
> > > > 2. It's what oracle explicitly states to do for a cold backup in their
> > > > documentation. See metalink note # 97495.1 updated last on
> 10-Jun-2002.
> > > > Though this document is geared for NT the principles of a cold backup
> are
> > > > the same. It clearly says to backup *all* database files (I take that
> to
> > > > mean tempfiles and datafiles since they are both part of the
> database), and
> > > > all online redo log files. There are a host of othe metalink documents
> that
> > > > deal with cold backups and all of them say the same thing. Get all
> database
> > > > files and online redo logs. It makes the recovery simpler.
> > >
> > > True, it simplifies recovery for databases in NOARCHIVELOG mode (though
> > > I hardly consider adding the word RESETLOGS to your "alter database
> > > open" command and adding in a tempfile or two to be complex). It can
> > > (will) cause serious problems for databases in ARCHIVELOG mode. Nothing
> > > in the note you referenced specifically states that the database is in
> > > ARCHIVELOG mode, so technically it is OK (though I still say it's a bad
> > > habit). But I would strongly encourage you to not follow the
> > > instructions in the Metalink note for an ARCHIVELOG database.
> > >
> > > Futhermore, that note was originally written for 8.0, before the advent
> > > of tempfiles. The script included does NOT back them up (it only
> > > selects from v$datafile). Also note the disclaimer "The sample program
> > > in this article is provided for educational purposes only. It is NOT
> > > supported by Oracle Support Services."
> > >
> > > I'd be surprised if you could produce a Metalink document that advocates
> > > 1) backing up online redo logs explicity for archivelog mode databases
> > > or 2) explicit references to backing up a tempfile.
> > >
> > > Regards,
> > > Sean
> >
> > And, I might add, if it is a production database and is not in ARCHIVELOG
> mode
> > exactly what is the value of the transaction being processed? Apparently
> zero.
> > Apparently you it is ok to lose the last eleven hours of transactions as
> long as
> > you have the last fifteen minutes.
> >
> > Daniel Morgan
> >

Which would clearly indicate that there are no transactions worth recovering. So of what possible value are the log files?

Daniel Morgan Received on Wed Jul 03 2002 - 10:18:47 CDT