RE: Re:Hot Backup using EMC /BCV splits

If you haven't tested a recovery, then it's probably a good idea to begin a project called "Test Recovery" right away. All it takes is one test that fails to recover, and it kills all the arguments and opinions about why it should have worked.

Cary Millsap
Hotsos Enterprises, Ltd.
http://www.hotsos.com

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-----Original Message-----
Sent: Thursday, August 15, 2002 12:09 PM To: Multiple recipients of list ORACLE-L

Thanks a lot for all your resposes.

The arugment our SA has is, the split that we doing is an instant split and
he says Hot backup mode is required only if it is a Normal BCV split.

All this argument started when we were trying setup a clone of our production database using the split copy. When we tried to recreate the control file with different SID, we got following error in our alert log for
all our datafiles and control file creation failed.

"WARNING! Recovering data file 1 from a fuzzy file. If not the current file
it might be an online backup taken without entering the begin backup command."

We again refreshed our split and tried to bring up the database without recreating the controlfile.
Database came up without any problems and it is running till now without any
problems. So the point now he is making is there is nothing wrong in the
process of backup and there is no need to alter the script to move the split
before end backup.

• Original Message ----- To: "Multiple recipients of list ORACLE-L" <ORACLE-L_at_fatcity.com> Sent: Thursday, August 15, 2002 11:23 AM

> Nate,
>
> We are using EMC and BCV's each night to create both backups and a
reporting
> database. Your SA has it WRONG.
>
> 1) Put all tablespaces in hot backup mode
> 2) sleep 5
> 3) split the bcv
> 4) return tablespaces to normal
>
> The reason that this is important has nothing in the world to do with
EMC
and
> everything to do with Oracle. Since switching the database files into
and
out
> of hot backup causes an immediate write to the file headers locking or
unlocking
> the SCN. Consequently your backups are inconsistent and consequently
worthless.
> The reason is that when you enter hotbackup mode all of the file
SCN's
are
> frozen giving Oracle a known starting point for recovery's sake. By
switching
> back to normal mode the RDBMS has no idea of which transactions are in
the
files
> and which are not. It assumes that it is seeing an instance crash and
will only
> use the on-line redo. Your DB will come up, but don't expect it to
stay
that
> way, ours crashed with "block corruption" 45 minutes later. Believe
me,
we
> tried it due to a misinformed EMC person(that doesn't happen does it?)
&
failed.
>
> Dick Goulet
>
> ____________________Reply Separator____________________
> Author: "Nat" <nat2710_at_hotmail.com>
> Date: 8/15/2002 6:58 AM
>
> Hello,
>
> We are on IBM AIX 4.3.3 with EMC and BCVs. Our Unix admin has setup
the
> backups for the database in following sequence to do the Hot backup.
>
> 1. Put all tablespaces in the database in Hot backup mode
> 2. Sleep 5
> 3. Put all the tablespaces back into normal mode
> 4. Split the BCV's
> 5. Mount on another machine and backed up from it.
>
> What I am concerned is with step 4. Split BCV's should be done at
step 2
> instead of step 4.
> According to our Unix Admin, EMC takes care of consistency and there
is no
> need for any concern. As per him the split is instant split and EMC
> guarantees consistency.
>
> What do you all think. What is the recommended procedure.
>
> TIA,
>
> Nate
>
>
>
>
> --
> Please see the official ORACLE-L FAQ: http://www.orafaq.com
> --
> Author: Nat
> INET: nat2710_at_hotmail.com
>
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-- 
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-- 
Author: Nat
  INET: nat2710_at_hotmail.com

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-- 
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-- 
Author: Cary Millsap
  INET: cary.millsap_at_hotsos.com

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