REPOST: Re: Online Backup Doubt

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

--
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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


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