quarkman <quarkman_at_myrealbox.com> wrote in message news:<oprtnpxgpuzkogxn_at_haydn>...
> On Sat, 9 Aug 2003 17:18:12 +0200, Anton Buijs <remove_aammbuijs_at_xs4all.nl>
>
> >
> > It's Burton's remark to backup the redo files and I did not react on it
> > because frankly I am in favor to backup the online redos when:
> > a. the database runs in noarchivelogmode
> > b. and you don't use rman to make backups (rman never backup redos
> > anyway)
> > For 2 reasons:
> > a. if you did a shutdown abort you need them to recover the database
>
> If you lose all your redo logs, and you're not in archivelog mode, you'd
> restore your previous closed backup (which is consistent and doesn't
> contain redo logs), and you'd say 'recover database until
> cancel...cancel...alter database open resetlogs'. You've now got a fresh
> set of redo logs and the database can be opened. So there was no need to
> back the logs up.
>
> > b. when you have them you can normally open the database and you have a
> > real
> > complete set; without the redologs you must do an open resetlogs.
>
> See, even you know it can be done without having a backup set of logs on
> hand.
>
> > Your reaction will probably be: "make sure you do a clean shutdown" and
> > "what the heck, open resetlogs isn't so bad" but my reaction would be:
> > not a
> > problem to backup the redo's too and I am protected against these 2
> > possible
> > mistakes.
>
> But vulnerable to a much worse one, which is restoring stale logs on top of
> usefully fresh ones (and I've seen it done), when you've gotten into the
> habit of restoring *.* from a backup directory on a noarchivelog test
> system, and survived, and then do much the same on the archivelog
> production system, and burn miserably as a result.
>
> Maybe I'm simplistic, but I like wherever possible to have one set of
> guidelines which cover all eventualities... wherever possible. And the
> advice 'don't backup redo logs ever' works under all circumstances,
> whatever the characteristics of your database happens to be, and is safe.
>
> But you obviously know all the issues, so that's fine.
>
> ~QM
>
>
>
>
>
> >
> > For a database in archivelogmode I agree: never backup the redologs
> > because
> > you probably do a roll forward and have the archives available for that
> > purpose. And you can't be tempted to restore them, loosing the real ones
> > and
> > therefore loosing transactions.
> >
> > Altough a "best practice" would be to always make a savety copy of a
> > control
> > file and redolog files and if possible the entire database or involved
> > files
> > before beginning a restore/recovery.
> >
> >
> >
hey, pple! thanks for the insightful postings... definitely helping me...
Received on Sun Aug 10 2003 - 10:52:45 CDT
