Re: about logfiles

"Howard J. Rogers" <hjr_at_dizwell.com> wrote in message news:<3f91a4b1$0$21651$afc38c87_at_news.optusnet.com.au>...
> mohanasundaram wrote:
>
> > Hai,
> >
> > I have database with two log groups, each of this contain two
> > logfiles.
>
>
> We refer to those two files as MEMBERS of the log group.
>
> > At a movement, i am delete one logfile.
>
> Please don't. Deleting log files means (potentially) lost data. On the other
> hand, I'm not clear whether you are talking about deleting one of your log
> groups, or deleting one of the members from one of your log groups.
>
> >and now i have one log file
> > which is current.
>
> If you had two log groups, and you entirely get rid of one of those groups,
> then your database will be stuffed, although you might not have actually
> lost any data yet.
>
> >In some situation this file will deleted due to some
> > problem.
>
> If you now drop the other group, especially if it is the current log group,
> then you have definitely just lost data.
>
> > Then what is the Database position ? Is it mount mode, or in
> > openmode?
>
> You will not be able to get a database open if the controlfile thinks it has
> two working redo log groups, and you've arranged for there to be just one,
> or even none. If you try a 'startup' command, you will fall over into the
> mount state (ie, the controlfile can be read correctly, but something about
> the data files and redo logs prevents the database going on into the fully
> open state).
>
> If, on the other hand, you delete MEMBERS from log groups, that will not
> prevent the database from being opened. Provided the control file can find
> one working member from each group, the database can be opened. That's why,
> of course, you are strongly recommend to have "multiplexed" redo logs in
> the first place (ie, groups with more than one member) so that you have
> some resilience and redundancy. A member can disappear, and the database
> will continue to work normally. But if an entire group disappaears, your
> database will crash, be unable to be re-opened, and you may well have lost
> committed data.
>
> > plz answer me.
>
> Be precise in the terminology you use. Groups and members. And then the
> answers will be clearer for you.
>
> Regards
> HJR
Its been awhile since I tried it, but I don't believe that oracle will allow for there to be less than 2 redo log groups.

A redo log switch with only one group? Sounds like one hand clapping, to me.

It then follows that he was not able to remove one of only 2 log groups.
I would have to think that he removed a member of a redo log group.

His original post lacked enough info in an intelligible format to be considered to be worthy of replying to.

The only advice I would have for him was to restore the affected files from the cold backup that he made prior to even thinking about removing redo log members.

Pd Received on Sun Oct 19 2003 - 13:32:27 CDT