Re: Two questions for Oracle

From: Howard J. Rogers <hjr_at_dizwell.com>
Date: Wed, 23 Jun 2004 14:42:58 +1000
Message-ID: <40d90a35$0$18190$afc38c87@news.optusnet.com.au>

"Mark D Powell" <Mark.Powell_at_eds.com> wrote in message news:2687bb95.0406221623.6b78839d_at_posting.google.com...
> Frank van Bortel <fvanbortel_at_netscape.net> wrote in message
news:<cb9rfv$hbl$1_at_news2.tilbu1.nb.home.nl>...
> > DB2 Convert wrote:
> >
> > > Hi,
> > >
> > > I have two questions about Oracle.
> > >
> > > 1. Waht will actually happen when one location of the logs
> > > (multiplexing) are down? will Oracle just ignore it?
> >
> > What options did you set? Ignore it, or halt 'till repaired?
> >
> > >
> > > 2.Is there a way yet to turn on the archive log mode without shutting
> > > down the database?
> > >
> >
> > What options did the manual give you?

>

> You can find the instructions for switching archive log mode in the
> DBA Administration manual (ch 8 with version 9.2 doco) and you must
> bounce the database for all versions below 10. I am not sure with 10
> but this probably has not changed.

It hasn't. And as I explained in a previous post, it can't change. It would make no sense to do so, because your database would be unrecoverable. At the very least, you need redo generated from a known point of total database consistency to even give yourself a chance of recovering anything. But practically, you need a new backup to be taken from just prior to the moment you went into archivelog mode, and that backup must be a closed, consistent one. So the requirement for shut down is not going to be going away any time soon.

> I am not sure what parameters Frank is talking about in relation to
> the behavior of the online redo logs when one member of a group is
> non-accessible.

He wasn't. Frank was talking about log_archive_dest_n parameters for archived redo logs.

>There are parameters for copying the redo logs to a

> standby db, but I am not aware of any for the online logs within the
> primary database for varing error handling.

There aren't any for online logs.

> In the DBA Administration manual chapter on managing the redo logs (ch
> 7 in ver 9.2 doco) Oracle stats that the behavior varies based on the
> exact problem but the most common behavior is for Oracle to log a
> message in the Alert log and in the log writer (lgwr) trace file while
> continuing to operate with the remaining logs members in the log group
> so long as at least one group member is accessible.

True.

Regards
HJR Received on Tue Jun 22 2004 - 23:42:58 CDT