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REPOST: Re: Online Backup Doubt

From: Augustine Joseph <kunjaathi_at_hotmail.com>
Date: 30 Dec 2001 21:29:19 -0800
Message-ID: <7$--$$-$-%--%-%%_$@news.noc.cabal.int>


Hi,

I made a mistake when I mentioned about DB restoration. What I actually meant was I've tried "DB recovery".

I've tried a DB recovery and I got "... needa media recovery" when my backup script has got the 'host copy ..' statement which was executed inside the oracle. That's how I assumed the backup has been invalid.

I've done few tests and I'm very much sure that the problem was there. But what I don't understand why this DB file was not synhcronised.

Below is how I tested.

My Original script(Backup was invalid in this case, prompted for the media recovery for system01.dbf)

svrmgrl <<EOF
connect internal
alter tablespace SYSTEM begin backup;
host `cp -p /u01/datafiles/DB/system01.dbf /u02/backup/DB/.` alter tablespace SYSTEM end backup;

....................

quit
EOF My test script (This time system01.dbf was OK. But the next DB file tools01.dbf
prompted for media recovery, for which 'copy' was executed within oracle)

svrmgrl <<EOF
connect internal
alter tablespace SYSTEM begin backup;
quit
EOF
cp -p /u01/datafiles/DB/system01.dbf /u02/backup/DB/.

svrmgrl <<EOF
connect internal
alter tablespace SYSTEM end backup;

alter tablespace tools begin backup;
.....

quit
EOF Regarding the control trace file I'm confused. If I've a hot backup and control trace, and say all my control files been corrupted, can you please suggest what are the steps I need to follow to recreate the control files and bring up the DB?

Tx
Augustine

"Howard J. Rogers" <dba_at_hjrdba.com> wrote in message news:<3c2f64e9$0$2599$afc38c87_at_news.optusnet.com.au>...
> Restoring a backup doesn't test anything, apart from your abilities to issue
> appropriate restore commands. The real test comes when Oracle proclaims
> that "file X is inconsistent and needs media recovery"... if you are, at
> that point, unable to apply archives/redo to the file to make it consistent,
> and can't thereafter issue the 'alter database open' command then sure, the
> file was toast. But if you get the 'media recovery complete' message, and
> are then able to open the database successfully, it would suggest the file
> was fine.
>
> If you read my original reply again, you'll notice that the discussion about
> when the tracefile backup of the controlfile is useful contained not one
> mention of hot or cold backups. The question of whether to take the trace
> version as opposed to the binary version backup is a matter of the eventual
> use that can be made of each version during a recovery scenario. Either
> method works fine hot or cold. The trace script is useful for those rare
> occasions when all multiplexed versions of the controlfile are lost or are
> corrupt; the binary backup is useful for when user errors result in a
> physical alteration to the database (such as inadvertently dropping a
> tablespace). You should do both.
>
> Regards
> HJR
> --
> ----------------------------------------------
> Resources for Oracle: http://www.hjrdba.com
> ===============================
>
>
> "Augustine Joseph" <kunjaathi_at_hotmail.com> wrote in message
> news:bde72cc6.0112292010.6a9c3b00_at_posting.google.com...
> > Hi,
> >
> > The trace file is useful in the case of cold backup. Is it corrct?
> >
> > ">> I'd be interested to know how you *know* the backup is invalid."
> >
> > I tested the backup by restoring it.
> >
> > Tx
> > Augustine
> >
> >
> > "Howard J. Rogers" <dba_at_hjrdba.com> wrote in message
> news:<3c2e3cbd$0$5269$afc38c87_at_news.optusnet.com.au>...
> > > Comments below
> > > HJR
> > > --
> > > ----------------------------------------------
> > > Resources for Oracle: http://www.hjrdba.com
> > > ===============================
> > >
> > >
> > > "Augustine Joseph" <kunjaathi_at_hotmail.com> wrote in message
> > > news:bde72cc6.0112282014.40efabf3_at_posting.google.com...
> > > > Hi,
> > > >
> > > > 1) For online backup is it mandatory that the 'backup controlfile' be
> > > > executed at the end of the backup process. I mean after all the
> > > > tablespacess are backed up.
> > > >
> > >
> > > Nothing is "mandatory". It's up to you whether you want a backup of
> your
> > > control file -which happens to be just as an intrinsic part of your
> database
> > > as the datafile/tablespaces you've carefully backed up. Commonsense
> would
> > > suggest that you *should* take a backup of it, though whther that's a
> binary
> > > backup or atrace file backup is more open to discussion. Personally,
> I'd
> > > recommend nightly trace file backups and weekly binary ones. The point
> > > being is that the trace file version is an extremely easy way of
> recovering
> > > from total controlfile loss, but the binary version is useful if a
> > > tablespace ever gets dropped.
> > >
> > > > 2) I've this statement in my unix script(Solaris)
> > > >
> > > > Alter tablespace AJAPP begin backup;
> > > > host`cp /u01/datafiles/db/aj.dbf /bkp/datafiles/aj/aj.dbf`
> > > > Alter tablespace AJAPP end backup;
> > > >
> > > > does the oracle waits the copy to be completed before proceeds with
> > > > the 'alter' statement.
> > >
> > > I rather think it depends on Unix. Al I can tell you is that, on
> Windows
> > > 2000, if you have a SQL script containing the lines...
> > >
> > > alter tablespace system begin backup;
> > > host copy d:\oracle\oradata\db2\system01.dbf d:\backup1.dbf
> > > alter tablespace system end backup;
> > >
> > > ...then SQL Plus performs the actions synchronously, waiting for each
> one to
> > > finish before moving on to the next (meaning the backup is useful and
> > > valid). I can't comment as to whether Solaris works the same way -though
> > > it's not difficult to knock up a three-line script and then run it
> within
> > > SQL Plus and watch to see what happens. If this is a *shell* script
> you're
> > > running, and not a SQL script, someone who knows the O/S will have to
> > > comment.
> > >
> > > >I'm getting invalid online backup. My doubt is
> > > > here.
> > > >
> > >
> > > I'd be interested to know how you *know* the backup is invalid.
> > >
> > > Regards
> > > HJR
> > >
> > >
> > >
> > > > If i come out of oracle(svrmgrl) after alter begin statement and does
> > > > a OS copy, backup is valid.
> > > >
> > > > Any ideas?
> > > >
> > > > Thanks
> > > > Augusitne

autocancel Received on Sun Dec 30 2001 - 23:29:19 CST

Original text of this message

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