Comment below.
Regards
HJR
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Resources for Oracle: http://www.hjrdba.com
===============================
"Thomas Kyte" <tkyte_at_us.oracle.com> wrote in message
news:a0kst202k0t_at_drn.newsguy.com...
> In article <oSaX7.2057$ju5.445105_at_news.uswest.net>, dsmcd says...
> >
> >
> >>You will not be able to do a point in time recovery from an o/s-level
> >>(ie,
> >>cold) backup. There would be no point. It doesn't make sense.
> >
> >Sorry, I wasn't clear. I am duplexing my archived redo logs. One set is
> >on a different pair of mirrored drives than where the tablespaces live.
> >Same for the control files. *Assuming* a failure between backups, and
> >*assuming* I could retrieve one good set of redo logs and a good
> >control file, I should be able to restore the tablespaces from cold
> >backup and then use the good control file and running the good redo
> >logs from that point forward, getting me to the point of failure.
> >Correct?
> >
>
> yes.
> as long as you are in archive log mode and have all of the logs since the
last
> backup. It is a good practice indeed to keep at LEAST two or three
backups and
> all needed logs.
>
> >
> >>Archivelog mode is critical (required) for a hot-backup, so I would
> >>say that
> >>they do, in fact, come into play.
> >
> >Yes, archivelog mode is required for hot, but does not rule out cold,
> >correct?
> >
>
> correct -- but doing HOT is not any harder then cold really (for some
reason it
> "sounds scarier" to people but its not). You need to go through the same
steps
> during a recovery regardless of hot or cold.
>
I'd respectfully disagree with that, sort of. Hot backups are fiddlier than
cold -you've got to remember to put things into hot backup mode, and take
them out. And you've got to remember to do it for every tablespace. And
(if you follow the published advice) you've got to remember to issue a
checkpoint as each tablespace comes out of hot backup mode. And if there's
an instance failure during the backup, your database won't restart until you
remember to take the datafiles out of hot backup mode... though there's a
dire warning about media recovery being required just to throw you a bit.
Colds just require a single shutdown and the equivalent of a 'copy *.*'
command. Assuming I didn't mind the downtime, and assuming I could live with
the cold caches after startup, I know which I'd find less hassle to perform,
given the choice.
But it is perfectly true to say that however you perform your backups, the
recovery steps are the same in all cases (assuming archivelog mode, of
course).
Of course, if I had the choice, I'd be doing RMAN hot backups in 9i...
'backup database;' has a certain elegance about it!
Regards
HJR
>
>
> >>Sign up for the Oracle Technology Network at http://otn.oracle.com and
> >>then
> >>read this document:
> >
> >Definately will. Thanks.
> >
> >Thanks for your help. I appreciate it...
> >D.
> >
>
> --
> Thomas Kyte (tkyte@us.oracle.com) http://asktom.oracle.com/
> Expert one on one Oracle, programming techniques and solutions for Oracle.
> http://www.amazon.com/exec/obidos/ASIN/1861004826/
> Opinions are mine and do not necessarily reflect those of Oracle Corp
>
Received on Sat Dec 29 2001 - 16:33:19 CST
