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Re: backup of offline dropped datafile

From: Mindaugas Navickas <mnavickas_at_yahoo.com>
Date: 2005-12-23 19:16:36
Message-id: 20051223181636.80044.qmail@web30108.mail.mud.yahoo.com


Tanel, Koen

I do not think that Oracle would ever request a space from a datafile that is offline.
From the scenario that Koen described, it doesn't look that storage been allocated for any objects in the dropped data file, so queries against objects shoudn't fail.
Even if you recreate controlfiles/resetlogs (from backup or from trace), offline datafile will still apear in v$datafile - there is nothing you can do about it - but from my understanding it should not cause any issue.

Regards
Mindaugas Navickas
OCP
--- Tanel Põder wrote:

> Hi,
>
> If your queries fail because of unaccessible data in this datafile then
> there's not much you can do.
>
> If you add another datafile then you might get errors when segments need to
> extend (into the offline datafile), this could be worked around by
> preallocating extents for your segments. (it might not be enough when you're
> doing direct path inserts though).
>
> From recovery part I don't see any other problems than additional complexity
> and running with a tablespace in an abnormal state. I wouldn't personally
> like to run my production database in such mode at all.
>
> Tanel.
>
> ----- Original Message -----
> From: "Koen Van Langenhove"
> To:
> Sent: Friday, December 23, 2005 9:38 AM
> Subject: backup of offline dropped datafile
>
>
> > Hi,
> > First things first:
> > - 9.2.0.4 2-node RAC
> > - solaris 8 / sun cluster 3.0
> > - VxVM 3.2
> > - production system, rather urgent
> >
> > we have this little situation where someone dropped a datafile using
> > 'offline drop'. This was apparently not the best solution for its problem
> > and we don't have archivelogs available to recover the datafile (only the
> > archivelogs created during the backup are kept .. don't ask ..).
> >
> > As I understand it right now, there's no way we can "undrop" this
> > datafile, our only option is to drop the tablespace and recreate it, which
> > is what we'll do eventually. To get out of this situation we would like to
> > continue for a while with this datafile dropped, while adding another
> > datafile to make up for the lost space.
> >
> > Now, the question is, is this a good idea ? My main concern is
> > backup/recovery, but any other hints would be highly appreciated.
> >
> > TIA,
> > Koen
> >
> > PS the original problem:
> > - added a datafile
> > - the second node didn't have its symlink to the new vxvm volume
> > - adding the datafile worked, everything fine on node 1
> > - on node 2, got ORA-01157 on the new datafile
> > - created symlink but the instance did not pick up the datafile
> > - offline drop the datafile to bring the db into service again (while a
> > 'alter system check datafiles' would have fixed it)
> >
> > --
> > Regards,
> > Koen
> >
> > Siemens COM
> > COM D MN A
> >
> > Email : Koen.Van_Langenhove_at_siemens.com
> > - - - - - - - Unix IS user-friendly .., it's just quite picky about its
> > friends.
> >
> > --
> > http://www.freelists.org/webpage/oracle-l
> >
> >
>
> --
> http://www.freelists.org/webpage/oracle-l
>
>
>
                                  



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Received on Fri Dec 23 2005 - 19:16:36 CST

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