Re: Backup planning experience

In article <3a831e10_at_news.iprimus.com.au>,   "Howard J. Rogers" <howardjr_at_www.com> wrote:
>
> "Andreas Schlager" <aschlager_at_eunet.at> wrote in message
> news:imBg6.169$Q3.3177_at_nreader1.kpnqwest.net...
> > alexberi_at_my-deja.com wrote in <95tuch$df3$1_at_nnrp1.deja.com>:
> >
> > >
> > >-Is it a good idea to backup the whole database incrementaly or to
> > >treat the table separatelly?
> > >-What about the partitions?
> > >-If the database can be shutdown during the night do I need to
 backup
> > >archive logs?
> > >-the output device is a tape, do I need a different tape for each
 daily
> > >backup?
> >
> > Hi Alex,
> >
> > I don't know RMAN in detail.
> > if you want to keep the database running 7x24, you have to set the
 db in
> > backup-mode (alter database begin backup or somehow),
>
> Close, but no banana. The command is alter TABLESPACE x begin backup.
 And
> having issued that for a tablespace, you can then copy the relevant
> datafiles *for that tablespace only*, and then issue the alter
 tablespace x
> end backup command. Then you move onto the next tablespace.
>
> >backup ALL DB-Files,
> > then alter database end backup, and now all archives generated
 during
> > backup until now.
> >
> > If you shut down your DB and if you backup ALL db-files (incl. redo
 logs,
> > contr. files), you should not need the archives (someone please
 correct me
> > if I'm wrong here).
> >
>
> You are wrong here. If you are in archivelog mode, you should ALWAYS
 backup
> your archives, since they are the only thing allowing complete
 recovery of
> all data after a media failure. Oracle hasn't introduced 5-way
 writing of
> archives in 8i just for fun, you know! If the database is shutdown
 for
> backup, it is permissible to take backups of your online redo logs,
 whether
> you are in archivelog mode or not. If you are doing hot backups, it
 is
> very, very foolish to copy your online redo logs (the copies will be
> internally inconsistent and utterly useless for recovery purposes).
>
> > I'm sure, you would need more than one tape - I'm sure you need a
 tape
> > library to backup 200 gigs. No chance at all to do it without. And
 use
> > *fast* tapes! Keep in mind, that in the case of disaster you need at
> > minimum the time to restore that it took to backup the data.
> >
>
> And for that reason, my strong advice is to acquire the hard disk
 capacity
> to backup onto disk first, and to take the tape backup from that copy.
>
> > If you plan to use incremental backups, also think about the time
 factor.
> > First, you have to restore a COMPLETE offline backup, then you have
 to
> > apply ALL following archives!!!
>
> Not true. If he's taking incremental backups, he must therefore be in
> archivelog mode (otherwise he *has* to perform closed, whole database
> backups). In archivelog mode, if one datafile bites the dust, it is
> perfectly legitimate to restore the one problem datafile and apply the
 redo
> from that point on, for that one file (hence the 'recover datafile x'
> command).
>
> >This could take a couple of days, if you
> > have to apply a lot of archives!
> >
> > I hope, that helps a little bit.
> >
> > If I'm wrong somewhere here, please correct me, group!
> >
>
> I think the two of you could both do with a swift trip to
> http://www.geocities.com/hjroz2000/backup_and_recovery.htm
>
> There's a document there that may be of some help in understanding the
> principles (and some RMAN examples).
>
> Regards
> HJR
>
> > Andy.
>
>

Imagine using offline backup.
What about the badest situation (all disks lost)? When I have to restore the whole database from backup media AND I have to use a backup controlfile.
Can I recover forward from a offline backup using backup controlfile? Or does Oracle finish recovery with the (consistent) SCN in all datafiles???
cu
Johannes

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***   each of them", the old, wise man said.       ***


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