Very Computer

My question is this when working with control files I understand that
I must use the alter database command to create a human readable text
file.  But would it be possible to just copy the file from one
directory to another?  Oh and would I need to do this durning system
maintenance or could I copy the file at anytime.

Thanks in advance

if you want to be able to recreate a lost control file you'd use
the 'alter datbase backup controlfile to trace' command and save the
resultant output as script to recreate the control file if you lose all
the multiplexed control files.

and if you're running NT, you won't be able to copy the control file
while your database is open, that's a sharing voilatoin for NT. I'm not
really sure about UNIX.

Quote:> Could there ever be a competent newbe question?  Oh well

> My question is this when working with control files I understand that
> I must use the alter database command to create a human readable text
> file.  But would it be possible to just copy the file from one
> directory to another?  Oh and would I need to do this durning system
> maintenance or could I copy the file at anytime.

> Thanks in advance

getting the meanin' of data...

Sent via Deja.com http://www.deja.com/
Before you buy.

Hope this helps you
Lehmann

Keth

On Thu, 5 Oct 2000 09:03:15 +0200, "Lehmann"

Quote:> Could there ever be a competent newbe question?  Oh well

> My question is this when working with control files I understand that
> I must use the alter database command to create a human readable text
> file.  But would it be possible to just copy the file from one
> directory to another?  Oh and would I need to do this durning system
> maintenance or could I copy the file at anytime.

> Thanks in advance

If the database is fully shut down, then you can copy it as though it were
any other file on your disk.

But the real issue is this: copying the controlfile is fine for when you
want to start out mirroring.  After that, binary versions of the controlfile
are a royal pain in the *to work with.  When you come to use an old
binary copy of the controlfile to recover a database that has lost all its
originals, you will be forced to open the database with a resetlogs -and
that means, nasically, that all prior backups and all prior archives (if
you're taking them) are rendered instantly worthless -they now relate to a
prior incarnation of the database, and can't be used for the present
incarnation (except under extraordinary circumstances).  Resetlogs is,
therefore, a VERY expensive option, and a binary image of the controlfile
will guarantee one.

The text script you mention (the 'backup controlfile to trace' trace file)
is much the preferred method of recovering from total controlfile loss,
provided you keep it up to date... using it, all required copies of the
controlfile are regenerated from scratch, with the system forcing the
highest SCN found amongst the datafiles into the header of the new
controlfiles.  Thus, there is no resetlogs, and all prior backups and
archives remain entirely useable.

Regards
HJR

regards,

:) ATTA

Quote:> invented -because Oracle is producing the copy, it is guaranteed
consistent.
> However, that command can indeed be issued at any time of the day or
night.

> If the database is fully shut down, then you can copy it as though it
were
> any other file on your disk.

> But the real issue is this: copying the controlfile is fine for when
you
> want to start out mirroring.  After that, binary versions of the
controlfile
> are a royal pain in the *to work with.  When you come to use an
old
> binary copy of the controlfile to recover a database that has lost
all its
> originals, you will be forced to open the database with a resetlogs -
and
> that means, nasically, that all prior backups and all prior archives
(if
> you're taking them) are rendered instantly worthless -they now relate
to a
> prior incarnation of the database, and can't be used for the present
> incarnation (except under extraordinary circumstances).

Resetlogs is,

Quote:> therefore, a VERY expensive option, and a binary image of the
controlfile
> will guarantee one.

> The text script you mention (the 'backup controlfile to trace' trace
file)
> is much the preferred method of recovering from total controlfile
loss,
> provided you keep it up to date... using it, all required copies of
the
> controlfile are regenerated from scratch, with the system forcing the
> highest SCN found amongst the datafiles into the header of the new
> controlfiles.  Thus, there is no resetlogs, and all prior backups and
> archives remain entirely useable.

> Regards
> HJR

getting the meanin' of data...

Sent via Deja.com http://www.veryComputer.com/
Before you buy.

Nevertheless, if the wind is blowing in the right direction, and the moon is
in the fourth quarter on an alternate Wednesday, then it is possible to
store the new controlfile out of harms way, bring back the old one and all
the old datafiles, do a recover until the checkpoint number that represented
the point at which you did the resetlogs, then bring back the new version of
the controlfile, and perform further recovery to bring the new incarnation
back up to date.  It's called 'recovery through resetlogs', and its
nerve-wracking stuff -and as I say if you can avoid it by the simple
expedient of taking a new backup straight after doing a resetlogs, you'd be
well advised to do so.

It's described in section 7.3 of the backup and recovery document I have on
my web site (page 40) -www.geocities.com/howardjr2000

Regards
HJR

Quote:> Resetlogs is,
> > therefore, a VERY expensive option, and a binary image of the
> controlfile
> > will guarantee one.

> > The text script you mention (the 'backup controlfile to trace' trace
> file)
> > is much the preferred method of recovering from total controlfile
> loss,
> > provided you keep it up to date... using it, all required copies of
> the
> > controlfile are regenerated from scratch, with the system forcing the
> > highest SCN found amongst the datafiles into the header of the new
> > controlfiles.  Thus, there is no resetlogs, and all prior backups and
> > archives remain entirely useable.

> > Regards
> > HJR

> --

> getting the meanin' of data...

> Sent via Deja.com http://www.veryComputer.com/
> Before you buy.