Re: quick hot backup question...

Howard,
Think offsite storage. This way I can take the tapes off site each day and if a fire happens later that day then I have everything and nothing in the redo (except of course after the switch). At least as of when I took the backup there is nothing in the redo (assuming a quiet time). You are correct I probably should be mirroring my archive logs to a system that is not in the same geographic location; that would be a better idea.

Jim

"Howard J. Rogers" <dba_at_hjrdba.com> wrote in message news:a7o4ju$vfn$1_at_lust.ihug.co.nz...
> If you're doing O/S online backups, then there's no need for a preliminary
> checkpoint, because that's precisely what the 'begin backup' command
forces
> (at least for the datafiles of the tablespace involved).
>
> The one about a preliminary log switch (presumably because you are about
to
> copy the archives) is always a curious one. Lots of people do it, and
I've
> never really understood why. Usually the justification is that without
it,
> you are short of the current redo log, so you may lose data. There's
> something to that, I suppose. But it's also usually (so I find) because
> people view a backup as an isolated event, whereas the truth of the matter
> is, of course, that what you don't backup tonight you will backup
tomorrow.
> So if there's a bit of current redo left unbacked up, who cares?? You'll
> get it when tomorrow's backup is performed, and in the meantime there's no
> possible risk of data loss because you've multiplexed your online redo
logs,
> and then mirrored them with hardware RAID. Haven't you?? ;-)
>
> The other thing that mystifies me about forcing a log switch in order to
get
> an archive of the current log is that it only makes another log the
current
> log. So you can *never* really be completely and utterly up-to-date with
> redo copies, unless you stop all your users doing things: there'll always
be
> a new piece of current redo which you haven't backed up today. Hence cold
> backups, of course.
>
> That said, a log switch does no real harm -except induce a
> performance-hitting checkpoint.
>
> Regards
> HJR
> --
> ------------------------------------------
> Resources for Oracle : www.hjrdba.com
> ============================
>
> "Glen A Stromquist" <gstromquist_at_nospamyahoo.com> wrote in message
> news:jpMn8.11561$EV.366849_at_news1.telusplanet.net...
> > In my online backup scripts I don't do a logfile switch or force a
> > checkpoint before copying the datafiles.
> >
> > Is this recommended by Oracle?
> >
> > I'm wondering if I overlooked something when writing my scripts, I have
> used
> > my online backups on occasion to create a clone db, so I know they
"work"
> > the way I'm doing it now, but I guess it can't hurt to build in a
logfile
> > switch and/or force a checkpoint as part of the script as well.
> >
> > Curious to hear what others do regarding this....
> >
> >
> > cheers!
> >
> >
>
>
Received on Mon Mar 25 2002 - 18:22:16 CST