<tears of happiness>
thank you, thank you, thank you...
</tears of happiness>
- Jeremiah Wilton <jwilton_at_speakeasy.net> wrote:
> With graceful standby failover (I demo'd it last
> year at OOW), you can switch
> back and forth, back and forth as many times as you
> want without recopying any
> database.
>
> Basically, when you fail over to a standby, you shut
> down the primary, apply all
> the archived redologs to the standby, then copy all
> the online logs and the
> controlfile from the primary to the standby. People
> who use incremental
> checkpoints (DB_BLOCK_MAX_DIRTY_TARGET) must do a
> 'create controlfile reuse
> database <blah> noresetlogs' at this point. Other
> people don't have to.
>
> Finally, you "recover database" to get the last one
> or two online logs and open
> the standby "noresetogs." The standby just picks up
> the chain of SCNs where the
> primary left off.
>
> The old primary can be immediately pressed into
> service as a standby. Just
> generate a standby controlfile on the new primary,
> copy it into place on the old
> primary and start it up as a standby database.
>
> You can go back and forth in this way as many times
> as you want, and one just
> picks up the chain of SCNs where the last one left
> off. You never get a
> divergence of changes.
>
> I have talked to people who found this out, and
> looked like they were going to
> cry, thinking of the countless hours they had spent
> after every standby
> failover, recopying to the standby to get it rollong
> forward again.
>
> In 9i, they have an "automated" graceful failover
> mechanism for standby
> database. I haven't taken a look at it yet.
> Probably it is a massive
> java-based GUI that instantly consumes 512Mb or RAM.
>
> --
> Jeremiah Wilton
> http://www.speakeasy.net/~jwilton
>
> On Tue, 26 Jun 2001, Koivu, Lisa wrote:
>
> > OK. I admit my knowledge on standby is minimal,
> having only read up on it,
> > fiddled with it and used the idea sparingly for
> migrations.
> >
> > However, Jeremiah, I'm very curious. You state
> that 'Must reinstantiate
> > standby after failover by recopying' is a
> misconception. Yes, like many of
> > the things you state below, the documentation does
> say that - once you open
> > a standby db in r/w mode, it is no longer a valid
> standby after switching
> > back to the primary.
> >
> > Can someone shed some light on why this is not
> true? It seemed to make
> > complete sense to me. I can see how opening a
> database read only will work
> > and not invalidate the standby, but r/w?
>
> --
> Please see the official ORACLE-L FAQ:
> http://www.orafaq.com
> --
> Author: Jeremiah Wilton
> INET: jwilton_at_speakeasy.net
>
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Received on Wed Jun 27 2001 - 10:09:56 CDT
