Recreating your control files

[Billy Verreynne]

Peter wrote:

> When you recreate your control files for a crash recovery, why would
> that be a safe thing to do?

I always do a daily backup of the control file to trace and then keep an
offline copy of the trace file. Not sure what others do, but this sits more
comfortable with me.. :-)

--
Billy

[Brian Peasland]

I create a binary backup of the control file and also dump the control
file to trace. That way, I have both. In most cases, I use the binary
backup of the control file. And in most cases, the dump to trace is only
used as a reference.

HTH,
Brian

Billy Verreynne wrote:

>
> Peter wrote:
>

> > When you recreate your control files for a crash recovery, why would
> > that be a safe thing to do?

>
> I always do a daily backup of the control file to trace and then keep an
> offline copy of the trace file. Not sure what others do, but this sits more
> comfortable with me.. :-)
>
> --
> Billy

--
================================================== =================

Brian Peasland
[email]oracle_dba@remove_spam.peasland.com[/email]

Remove the "remove_spam." from the email address to email me.


"I can give it to you cheap, quick, and good. Now pick two out of
the three"

[Quarkman]

"Peter" <peter@nomorenewsspammin.ca> wrote in message
news:0dflfvg3ij8s95vd1qgel0vtulp890nlm0@4ax.com...

> When you recreate your control files for a crash recovery, why would
> that be a safe thing to do?
>
> Thanks
>

I don't understand the question.

Who says you re-create the control files when you perform a crash recovery??

Crash recovery=instance recovery.

Instance recoveries are performed by saying 'startup'. Oracle does the rest.
And controlfiles don't come into it.

Or have I missed your point?

~QM

[Quarkman]

"Brian Peasland" <oracle_dba@remove_spam.peasland.com> wrote in message
news:3EFAF17F.55C966C4@remove_spam.peasland.com...

> I create a binary backup of the control file and also dump the control
> file to trace. That way, I have both. In most cases, I use the binary
> backup of the control file. And in most cases, the dump to trace is only
> used as a reference.

Well, each to his own.

Since use of the binary backup in a recovery situation *demands* a
'resetlogs', which renders all previous backups and archives non-useful
(unless you are prepared to jump through hoops) until you perform a new
complete backup, the use of the trace file version of the control file
backup is rather more than sensible.

<Deep breath>

There are no circumstances where you would use the binary version of the
backup where you couldn't equally well use the trace file version of the
backup, with considerably less cost to the on-going health and well-being of
your database. Not to mention your DBA.

</Deep Breath>

With one significant exception: if you use RMAN, without a catalogue, then
the trace file backup doesn't include all the repository information. And
then the binary backup might prove useful.

~QM

>
> HTH,
> Brian
>
> Billy Verreynne wrote:

> >
> > Peter wrote:
> >

> > > When you recreate your control files for a crash recovery, why would
> > > that be a safe thing to do?

> >
> > I always do a daily backup of the control file to trace and then keep an
> > offline copy of the trace file. Not sure what others do, but this sits

more

> > comfortable with me.. :-)
> >
> > --
> > Billy

>
> --
> ================================================== =================
>
> Brian Peasland
> [email]oracle_dba@remove_spam.peasland.com[/email]
>
> Remove the "remove_spam." from the email address to email me.
>
>
> "I can give it to you cheap, quick, and good. Now pick two out of
> the three"

[Peter]

On Sat, 28 Jun 2003 23:48:33 +1000, "Quarkman" <quarkman@nowhere>
wrote:

I meant you recreate controlfiles based on your binary or text version
of your controlfile backup. This may happen when your harddrive
crashes. I know you are thinking about the DB itself crashing, sorry
for the confusion.

Thanks

>
>"Peter" <peter@nomorenewsspammin.ca> wrote in message
>news:0dflfvg3ij8s95vd1qgel0vtulp890nlm0@4ax.com.. .

>> When you recreate your control files for a crash recovery, why would
>> that be a safe thing to do?
>>
>> Thanks
>>

>
>I don't understand the question.
>
>Who says you re-create the control files when you perform a crash recovery??
>
>Crash recovery=instance recovery.
>
>Instance recoveries are performed by saying 'startup'. Oracle does the rest.
>And controlfiles don't come into it.
>
>Or have I missed your point?
>
>~QM
>

[Peter]

On Sun, 29 Jun 2003 16:37:16 +1000, "Quarkman" <quarkman@nowhere>
wrote:

How do you recreate your controlfiles accurately from abckup? When you
recover your database from a media failure, how do you make sure that
your new controlfile wil relflect the latest configuration of the DB?

Thanks

>
>"Brian Peasland" <oracle_dba@remove_spam.peasland.com> wrote in message
>news:3EFAF17F.55C966C4@remove_spam.peasland.com.. .

>> I create a binary backup of the control file and also dump the control
>> file to trace. That way, I have both. In most cases, I use the binary
>> backup of the control file. And in most cases, the dump to trace is only
>> used as a reference.

>
>
>Well, each to his own.
>
>Since use of the binary backup in a recovery situation *demands* a
>'resetlogs', which renders all previous backups and archives non-useful
>(unless you are prepared to jump through hoops) until you perform a new
>complete backup, the use of the trace file version of the control file
>backup is rather more than sensible.
>
><Deep breath>
>
>There are no circumstances where you would use the binary version of the
>backup where you couldn't equally well use the trace file version of the
>backup, with considerably less cost to the on-going health and well-being of
>your database. Not to mention your DBA.
>
></Deep Breath>
>
>With one significant exception: if you use RMAN, without a catalogue, then
>the trace file backup doesn't include all the repository information. And
>then the binary backup might prove useful.
>
>~QM
>
>
>

>>
>> HTH,
>> Brian
>>
>> Billy Verreynne wrote:

>> >
>> > Peter wrote:
>> >
>> > > When you recreate your control files for a crash recovery, why would
>> > > that be a safe thing to do?
>> >
>> > I always do a daily backup of the control file to trace and then keep an
>> > offline copy of the trace file. Not sure what others do, but this sits

>more

>> > comfortable with me.. :-)
>> >
>> > --
>> > Billy

>>
>> --
>> ================================================== =================
>>
>> Brian Peasland
>> [email]oracle_dba@remove_spam.peasland.com[/email]
>>
>> Remove the "remove_spam." from the email address to email me.
>>
>>
>> "I can give it to you cheap, quick, and good. Now pick two out of
>> the three"

>

[Anna C. Dent]

Peter wrote:

> On Sun, 29 Jun 2003 16:37:16 +1000, "Quarkman" <quarkman@nowhere>
> wrote:
>
> How do you recreate your controlfiles accurately from abckup? When you
> recover your database from a media failure, how do you make sure that
> your new controlfile wil relflect the latest configuration of the DB?
>
> Thanks
>

This is easy to answer.
I can be sure that the new controlfile will reflect the latest
configuration, because daily I
ALTER DATABASE BACKUP CONTROLFILE TO TRACE;

and the copy the resultant file to two different disks
on two different hosts. Now I have three copies & have
ALWAYS been able to access at least one on them in an
emergency.

[Peter]

On Wed, 02 Jul 2003 17:25:23 -0700, "Anna C. Dent"
<anacedent@hotmail.com> wrote:

If you are performng a media recovery that requires datafiles to be
recovered to another location, thenyour backup control files will not
reflect the latest configuration of the DB right before the crash?
What is the strategy then?

Thanks

>Peter wrote:

>> On Sun, 29 Jun 2003 16:37:16 +1000, "Quarkman" <quarkman@nowhere>
>> wrote:
>>
>> How do you recreate your controlfiles accurately from abckup? When you
>> recover your database from a media failure, how do you make sure that
>> your new controlfile wil relflect the latest configuration of the DB?
>>
>> Thanks
>>

>This is easy to answer.
>I can be sure that the new controlfile will reflect the latest
>configuration, because daily I
>ALTER DATABASE BACKUP CONTROLFILE TO TRACE;
>
>and the copy the resultant file to two different disks
>on two different hosts. Now I have three copies & have
>ALWAYS been able to access at least one on them in an
>emergency.

[Anna C. Dent]

Peter wrote:

> On Wed, 02 Jul 2003 17:25:23 -0700, "Anna C. Dent"
> <anacedent@hotmail.com> wrote:
>
> If you are performng a media recovery that requires datafiles to be
> recovered to another location, thenyour backup control files will not
> reflect the latest configuration of the DB right before the crash?
> What is the strategy then?
>
> Thanks
>

1) see QUARKMAN's response
2) use vi