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Re: Standby database question

From: Howard J. Rogers <howardjr2000_at_yahoo.com.au>
Date: Mon, 11 Nov 2002 10:02:36 +1100
Message-ID: <0sBz9.74097$g9.208314@newsfeeds.bigpond.com>

"Richard Foote" <richard.foote_at_bigpond.com> wrote in message news:86Bz9.74089$g9.208116_at_newsfeeds.bigpond.com...
> "Howard J. Rogers" <howardjr2000_at_yahoo.com.au> wrote in message
> news:4kyz9.74020$g9.208056_at_newsfeeds.bigpond.com...
> > Well, a simple question, and it seems to have stirred up all sorts of
> > confusion in the replies!!
> >
> > Somewhere in all of the replies is the truth.
> >
> > The paths to datafiles can be different, because there's an init.ora
> > parameter that will do a transparent conversion from '/bing/bong/x.dbf'
on
> > primary to '/blah/bong/x.dbf' on standby.
> >
> > The O/S must be the same on primary and standby. You can't ship redo
from
> a
> > Unix box to an NT standby, for example. Neither can you ship Solaris
redo
> to
> > an HP standby. Can an HP10.10 box ship redo to an HP10.20 standby?
> > Perhaps... but it would be unsupported, and would be the first thing
> Oracle
> > Support would pick up on if asked. As such, it's certainly not
> recommended.
> > The requirement for the O/S to be the same is true even of the new
> 'logical
> > standby' facility in 9iR2.
> >
> > The *number* of datafiles (and their size etc) must be identical on both
> > primary and standby. You can *NOT* have a subset of your datafiles as a
> > standby. If you've 100 datafiles on primary, each of 500MB, you must
have
> > 100 datafiles on standby, each of 500MB. The reason? You'll be shipping
> > redo from primary to standby, and redo contains instructions such as "on
> > file 3, block 650, row 4, change column 4 to 600". So if you don't have
a
> > file 3, or if file 3 is smaller on standby, such that it doesn't have a
> > block 650, the whole thing is going to go down the drain.
>
> Hi Howard
>
> This question has raised some confusion.
>
> You *CAN* have a subset of your datafiles on the standby DB.
>
> You can make datafiles on the standby database "offline" which means that
> these files do not have to be copied across, are not recovered (the redo
is
> simply ignored, it doesn't cause any failures) and effectively results in
a
> subset of the datafiles being maintained on the standby.
>
> When you open the standby database, you simply drop the now stuffed
> tablespace and you're away.
>
> Cheers
>

I don't rate your chances of pulling this particular trick off under Data Guard conditions. Just for starters.

However: I must dash: it's the day to listen to the War Requiem. (BB, Op.66).

Regards
HJR
> Richard
>
>
Received on Sun Nov 10 2002 - 17:02:36 CST

Original text of this message

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