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Re: os backup

From: Randy Harris <randy_at_SpamFree.com>
Date: Thu, 17 Feb 2005 00:38:05 GMT
Message-ID: <NHRQd.8405$ng6.1451@newssvr17.news.prodigy.com>


"Syltrem" <syltremzulu_at_videotron.ca> wrote in message news:GTOQd.3045$df.110276_at_tor-nn1.netcom.ca...
> Hi
>
> Comments embedded
>
>
> "utkanbir" <hopehope_123_at_yahoo.com> a écrit dans le message de
> news:f6c90ebe.0502151314.1a07fb6a_at_posting.google.com...
> > Hi,
> >
> > Sorry for the confusion.Let me summarize what i do:
> >
> > this is my system:
> >
> > redhat linux 2.1 advanced server
> > 4 itanium processors.
> > oracle 9.2.0.5 rac with 2 nodes
> > ocfs
> > emc disk array raid 10
> > and this is a datawarehouse system.
> > data size is > 1.5TB.
> >
> >
> > 1. stop the dbservers.(i use rac on redhat linux ia64 and have 2 nodes)
> > 2. copy all the datafiles to tape.
> > 3. start the dbserver.
> >
>
> You mean that you shutdown the instances on both nodes?
> Doing so you perform a cold backup. This is not necessary (although not
> mandatory either) since the db is in archivelog mode.

I think what Ed told him earlier is correct. If he's not ALTERING the tablespace to BEGIN BACKUP, the archived logs aren't going to do him much good. If he has a failure, he can go back to his last cold backup, but he won't be able to recover from there. At least he's shutting the instances down so his cold backup should be good. Many don't.

> To perform an ONLINE backup, you need to do a few things (and the first
> being to keep the instance up and running)
> a) for each tablespace:
> alter tablespace xyz begin backup;
> $ backup its datafiles
> alter tablespace xyz end backup;
> alter system backup controlfile to trace; (a good thing to have)
> alter system backup controlfile to \somewhere\somefile.xxx
> alter system archive log current;
> $ backup the archived log files.
> Resulting in no downtime at all. Of course that will take the same amount
of
> time to perform.
>
> > my redo logs are archived periodically and db is in archivelog mode.
> >
> What do you mean by this? Redo logs will be archved by Oracle (provided
that
> LOG_ARCHIVE_START=TRUE) when they get full. Is something different
happening
> at your site?
>
>
> And to answer your original question, pls others correct me if I`m wrong,
> yes you can use the "oracle archived" redo logs to do a point-in-time, or
> complete, recovery of your database if you restore all the datafiles from
> one of your backups, mount the database and perform a recovery. You will
be
> prompted for the archived redo logs needed for the recovery.
> Just don't startup OPEN if you plan on doing a recovery. In this regards
> using a cold backup is much the same as using an online backup, to
recover.
>
> HTH
>
> >
> > It takes 12 hours to copy all the data files.
> >
> > Kind Regards,
> > hope
> >
>
>
> --
> Syltrem
>
> OpenVMS 7.3-1 + Oracle 8.1.7.4
> http://pages.infinit.net/syltrem (OpenVMS related web site, en français)
> ---zulu is not in my email address---
> >
> > "Syltrem" <syltremzulu_at_videotron.ca> wrote in message
> news:<bCnQd.2994$df.109470_at_tor-nn1.netcom.ca>...
> > > Since not enough info was given by the OP, nobody here can provide
> adequate
> > > advice.
> > >
> > > If the OP is still following this thread, pls provide more info on
what
> you
> > > exactly do.
> > >
> > > It's not clear if :
> > > you use ALTER TABLESPACE BEGIN/END BACKUP
> > > and that the db is in archivelog mode
> > > and that the redo log files that you backup are the archived, or the
> online
> > > ones.
> > >
> > > And remember that while it's a good thing to have a backup strategy,
> it's
> > > much better to have a recovery strategy, and better again to have
proven
> > > that it works.
> > >
> > > Regards,
> > >
> > > --
> > > Syltrem
> > >
> > > OpenVMS 7.3-1 + Oracle 8.1.7.4
> > > http://pages.infinit.net/syltrem (OpenVMS related web site, en
français)
> > > ---zulu is not in my email address---
> > > "Ed Stevens" <nospam_at_noway.nohow> a écrit dans le message de
> > > news:102211daammhc3imvrpndl841cnu1oue6b_at_4ax.com...
> > > > On 14 Feb 2005 05:00:49 -0800, hopehope_123_at_yahoo.com (utkanbir)
> > > > wrote:
> > > >
> > > > >Hi ,
> > > > >
> > > > >I have a question related to the backup strageties. For some
reasons
> i
> > > > >cant get rman backups but instead i backup data at os level , and
> > > > >archive redo logs periodically. I wonder whether it is possible to
> use
> > > > >my redo log backups for recovery purpose. Is it possible to restore
> > > > >some of the archived files from the backup set than apply redo logs
?
> > > > >
> > > > >Kind Regards,
> > > > >tolga
> > > >
> > > > When you say you're backing up or data at the os level ... are you
> > > > simply copying the files without telling Oracle? Without ALTER
> > > > TABLESPACE ... BEGIN BACKUP? Because if so, your backups are pretty
> > > > much worthless. If I were in your boots, I'd be solving WHY I can't
> > > > get rman backups . . . .
> > > > Thanks.
> > > >
> > > > - Ed Stevens
> > > >
> > > > Cohn's Law: The more time you spend in reporting on what you are
> doing,
> > > the less time you have to do anything. Stability is achieved when you
> spend
> > > all your time doing nothing but reporting on the nothing you are
doing.
>
>
Received on Wed Feb 16 2005 - 18:38:05 CST

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