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Re: Questions about applying archive logs

From: Richard Foote <richard.foote_at_bigpond.com>
Date: Tue, 15 Oct 2002 23:24:51 +1000
Message-ID: <SuUq9.53445$g9.154640@newsfeeds.bigpond.com>


Hi Howard

Comments embedded.

"Howard J. Rogers" <howardjr2000_at_yahoo.com.au> wrote in message news:eoFq9.52652$g9.153554_at_newsfeeds.bigpond.com...
> Beg to differ, Richard.

Oooo , you know how I love it when you beg ;)

>
> "Richard Foote" <richard.foote_at_bigpond.com> wrote in message
> news:1Jzq9.52609$g9.153292_at_newsfeeds.bigpond.com...
> > Hi Hub,
> >
> > Ahh well, let's try again ;)
> >
> > There's no way to automate this from an Oracle perspective as such.
> >
> > You need a mechanism to copy the archived redo logs across to the
standby
> > server (which you already do). You then need to have the standby
(clone)
>
> The standby isn't a clone. He has to have a special form of the
controlfile
> that permits continuous recovery (alter database create standby
> controlfile).
>
> > database mounted (via the backed database files) and in recovery mode
via
> a
> > "recovery database until cancel using backup controlfile' command.
>
> And unless I'm much mistaken the recovery command is 'recover standby
> database'.
>
> >It will
> > then continually request redo logs to be applied. You then need a
> mechanism
> > to apply these or execute this command automatically, again perhaps via
a
> > cron job.
> >
> > You can then 'cancel' recovery after the 'last' redo log and open the
> > database with the resetlogs option when appropriate. I don't see how you
> can
> > meaningfully open the database in read only mode and subsequently
continue
> > the recovery as resetlogs needs to be applied.
>
> Am I missing something here? Shutdown immediate, followed by startup
mount,
> followed by alter database open read only. There's no resetlogs required
> when opening a standby database read only, only when you issue the command
> 'alter database activate standby database' (turning it into the new
> primary).
>
> I *know* you know these things, so I have a lurking suspicion I must have
> missed something that caused you not to give the above replies. Would
love
> to know what it is.

I know you know that I know, ... I think.

I was all excited in my first post in this thread regarding the use of Data Guard. Everything you've mentioned here is of course correct regarding the use Data Guard (Standby DB)

But ...

>
> It's not that he's only got the Standard Edition, is it? I was under the
> impression that SE did NOT mean you couldn't do standby database, only
that
> you couldn't do MANAGED standby. Maybe I've got that wrong, too?

There I go saying posters should include their DB versions and when they do, I fail to read it properly. The Standard Edition was indeed relevant as it doesn't support Data Guard (Prod DB must be on Enterprise Edition to support Data Guard). Therefore my first post kinda gets thrown out the window somewhat.

Therefore, in this post I was indeed referring to just a Clone DB rather than a Standby DB.

And in terms of opening the clone DB for read only purposes in the manner suggested by the OP, it's all a bit tricky without subsequently performing a recovery across DB incantations.

Sorry for any confusion.

Cheers

Richard
>
> Regards
> HJR
>
>
>
> >Other than repeating the
> > whole process with a fresh backup again. Perhaps someone else can help
you
> > with that one.
> >
> > Good Luck
> >
> > Richard
> >
> > "Hub" <hub_at_houston.rr.NOSPAM.com> wrote in message
> > news:Ptzq9.127992$8o3.3785512_at_twister.austin.rr.com...
> > >
> > > Hi Richard,
> > >
> > > Thanks for the help.. However we're using Standard Edition, not EE..
so
> > no
> > > dataguard for us.
> > >
> > > So I'm back to my original main question.. What is the
syntax/technique
> > for
> > > taking the latest archive and redo logs and applying against the cold
> > backup
> > > files I have on another server..and what is a good way to
automatically
> > > apply those logs as they come across.
> > >
> > > thx.. Allen
> > >
> > > ps I will read the dataguard stuff even if we can't use it..
> > >
> > > "Richard Foote" <richard.foote_at_bigpond.com> wrote in message
> > > news:8zyq9.52488$g9.153346_at_newsfeeds.bigpond.com...
> > > >
> > > > "Hub" <hub_at_houston.rr.NOSPAM.com> wrote in message
> > > > news:NEsq9.125210$8o3.3755846_at_twister.austin.rr.com...
> > > > >
> > > > > Howdy ya'll..
> > > >
> > > > Let me guess. You're from India ;)
> > > >
> > > > I have some archive log questions. Oracle 9i, linux,
> > > > > standard edition.
> > > > >
> > > > > Ok our main prod server spits out archive logs. On a seperate
> standby
> > > > > server I have copies of all the cold backup files.. tablespace,
> logs,
> > > > > control, redo, etc.. Every 15 minutes I cron job rsync the
archive
> > logs
> > > > to
> > > > > the standby server. What should I do on the standby side to
> > > automatically
> > > > > apply these archive logs to the standby server as they arrive (or
> soon
> > > > > thereafter)?
> > > >
> > > > OK. Recommendation 1. Lookup the Data Guard Concepts manual and see
if
> > > > Oracle's Data Guard (or Standby DB) is the way to go. Based on what
> > you've
> > > > requested to do, I would suggest it is as everything can be nicely
> > > automated
> > > > and protected.
> > > >
> > > > So you need to create the standby DB on your standby server
(basically
> > > > copying the database files across, a special standby control file
> that's
> > > > initially created on the prod server and possibly creating a set of
> > > standby
> > > > redo log files). Then mount the database and put it in managed
> recovery
> > > mode
> > > > which will make the standby DB applied redo as and when it arrives.
> > > >
> > > > On the Prod DB, the log_archive_dest_n parameters have options that
> > > enables
> > > > Oracle to automatically transport the redo to the standby server via
> > > either
> > > > the ARCH or LGWR processes.
> > > >
> > > > > Then if for some reason we have to switch from the main prod
> > > > > server to the standby one.. what is the appropriate
technique/syntax
> > to
> > > > take
> > > > > the latest archive/redo files, apply them to the standby box,
bring
> > the
> > > > > database up on the standby server.. etc.. does the main prod
> server
> > > have
> > > > > to be down to do this or can it still be running?
> > > >
> > > > OK. Recommendation 2. Lookup the Data Guard Concepts manual and the
> > > various
> > > > options you have. You can either perform a graceful switchover which
> > > enables
> > > > you to swap the behaviours of the Prod/Standby database (and very
> easily
> > > > back again) or you can simply activate the standby DB which converts
> it
> > to
> > > > the 'Mainman'.
> > > >
> > > > >
> > > > > Also, how can i have this standby database be read-only, updated
as
> > the
> > > > > latest archive logs arrive, used for a report server..
> > > >
> > > > OK. Recommendation 3. Lookup the Data Guard Concepts manual and see
> how
> > > you
> > > > can take the standby DB out of recovery mode and open it as read
only.
> > At
> > > > this point, users can log on and execute their queries but of course
> the
> > > > database is no longer being maintained as such. But that's fine, any
> > > queries
> > > > that only requires historical data and isn't too fussed about having
> > > today's
> > > > data will be as happy as Larry. Then you can kick everyone off and
> place
> > > the
> > > > standby db back in recovery mode. Note that a Temp LMT is crucial
here
> > but
> > > > the Data Guard doco covers all of that.
> > > >
> > > > >
> > > > > Also these archive logs, can I apply them to another database
> somehow?
> > > > Just
> > > > > pick an archive log file and say "try to apply all of these
changes
> to
> > > > this
> > > > > database"?
> > > >
> > > > Yes. You can create a "clone" database (which you create from the
> > backups
> > > of
> > > > the Prod DB) and use the archive logs created since the backup to
get
> > the
> > > > clone as up to date as required. Note the database must be a clone
> > > database,
> > > > it can't just be any database for (I hope) obvious reasons.
> > > >
> > > > My last recommendation. Read up on Data Guard. There's a lot to
> Standby
> > > DBs
> > > > these days with many options that make what you appear to want to do
> > very
> > > > flexible and automated.
> > > >
> > > > Good Luck
> > > >
> > > > Richard
> > > >
> > > > >
> > > > > thx a bunch.. Hub
> > > > >
> > > > > hub_at_houston.rr.NOSPAM.com
> > > > >
> > > > >
> > > >
> > > >
> > >
> > >
> >
> >
>
>
Received on Tue Oct 15 2002 - 08:24:51 CDT

Original text of this message

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