Re: backup without archivelog mode

I've answered at length to your other post in this thread, where you make the exact same point. No, export doesn't count as a "hot backup" since it is a logical backup, not a physical one. The term "hot backup" specifically means taking a physical copy of the database files whilst the database is open, and in use. When, in short, the contents of the datafiles are changing.

Export is not a true backup at all, if you assume that a backup should protect you from data loss (guaranteed no loss of committed data, in other words). Exports are a snapshot, and as such they are instantly out of date, and the one thing you can guarantee about exports is that the day they are used to recover from some disaster or other is the day you've lost data from your database.

You might care to check out my web site, the Tips/Backup and Administration link, and the article there called "does export count as a backup".

Regards
HJR

--
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Resources for Oracle: http://www.hjrdba.com
===============================


"Sean Comar" <skbansal999_at_directvinternet.com> wrote in message
news:3c9d5ebb$1_3_at_nopics.sjc...


> HJR,

>

> In this particular case, can't we do full database export while the

database


> is running? I think, database export will preserve the data integrity even

> in hot mode.

>

> Thanks.

>

> "Howard J. Rogers" <dba_at_hjrdba.com> wrote in message

> news:a7hb54$9fg$1_at_lust.ihug.co.nz...

> > Archivelog mode simply means that you can guarantee recoverability of

all


> > transactions.  If you can guarantee recoverability by some other

> mechanism,

> > then no, you don't need archivelog mode.

> >

> > By that, I mean that these nightly loads must be coming from some

source.


> > If you can back that source up, and are prepared to repeat a nightly

load


> if

> > something happens to the database, who cares about archives?!  A lot of

> > sites, for example, will use SQL Loader to load millions of records from

a


> > text file.  Since the text file can be burnt to CD, or put on tape, the

> load

> > could be repeated if ever there was trouble on the database.

> >

> > But:  You can never, ever make a copy of any database file whilst the

> > database is running, without that copy being internally inconsistent.

And


> > only archive logs guarantee that you can make an internally inconsistent

> > datafile consistent.  So: your choice.  If you can repeat the loads, and

> > don't mind doing so, don't bother with archives.  But then all backups

> will

> > require that you shut your database down before making a backup.  And

> since

> > you mention a weekend shutdown window, it's sounding as though you will

> need

> > to sign up to perhaps repeating up to 6 or 7 nights'-worth of loads in

the


> > event of trouble (ie, you'd restore from the cold backup you took last

> > weekend, and therefore have to repeat that entire weeks' loads).

> >

> > If you want to take hot backups (which your use of the 'alter tablespace

> > Florence begin backup' command suggests you want to do) then you will

> > absolutely, positively have to be in archivelog mode.  There is no

> exception

> > to the rule that hot files cannot simply be copied.  It matters not the

> > slightest that no-one is doing anything but selects.  *Oracle* will be

> doing

> > things that cause the all-important SCNs to increment at unexpected

> > intervals -at which point, you wouldn't be able to use the hot-copied

> files.

> >

> > If your database is up when you take backups, regardless of what it's

> doing,

> > it's a hot backup.  You must behave as though it were a hot backup.  And

> hot

> > backups require archivelog mode.

> >

> > If that's a storage pain, do cold backups once a week, and be prepared

to


> > repeat data loads.

> >

> > The choice is entirely yours.

> >

> > Regards

> > HJR

> > --

> > ----------------------------------------------

> > Resources for Oracle: http://www.hjrdba.com

> > ===============================

> >

> >

> > "obakesan" <pellicle_at_hotmail.com> wrote in message

> > news:9baa2b9f.0203222306.388fb025_at_posting.google.com...

> > > HiYa

> > >

> > > if I have a database that is more like a datawarehouse in that it gets

> > > load files loaded into it nightly, but no other transactions take

> > > place

> > > that involve the update or insert of data during working hours, can I

> > > back this up with simply copying the datafiles, control files ...?

> > >

> > > I thought that there is no point in making archive redo logs as really

> > > all that will happen between sqlloads is some complex selects using

> > > packaged procedures, nothing that is transation oriented.

> > >

> > > If I copy the database files is there any meaning in issuing an

> > > alter tablespace boing_said_zebedee begin backup; command? will this

> > > be needed to gurantee consistency (in case a load is timed at the same

> > > point

> > > as the backup)? Is there any point in archiving redologs in this

> > > situation.

> > >

> > > Also I was thinking of a weekend down and full cold backup. As there

> > > will be no data loaded in this period, and no users on it either.

> > >

> > >

> > > thanks for your time

> >

> >

>

>