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RE: EMC BCV Splits and Hot Backup mode.

From: Koivu, Lisa <>
Date: Mon, 24 Sep 2001 10:04:00 -0700
Message-ID: <>

Hi Glenn,

Are your arclogs & redologs on the bcv? 

Think of it in the same manner as a hot backup - what if there was a large data load going at the time of the split.  There's no guarantee as to what data changes will make it on what mirror if you are splitting it.  Hot backup mode ensures data will not be lost by writing in blocks to the redologs.   Of course I am assuming your logs are not on bcv's.

At least that's the way we did it at my last employer.  If you have the facilities to try it with and without backup mode, that would be a really fun test...  unfortuanately I don't even have a Unix box  ;(

Lisa Koivu
Oracle Database Administrator
Fairfield Resorts, Inc.

-----Original Message-----

From:   Glenn Travis []
Sent:   Monday, September 24, 2001 1:40 PM
To:     Multiple recipients of list ORACLE-L
Subject:        EMC BCV Splits and Hot Backup mode.

It  is my understanding that the common implementation of copying an Oracle database on an EMC using BCVs is this;

  1. put the source database in BEGIN BACKUP mode for all the tablespaces,
  2. break the mirror,
  3. put tablespaces in END BACKUP mode
  4. recover on target, or backup the files.

Why is it necessary to put the database in 'hot backup' mode when splitting a BCV?  If it is just like splitting a mirror, why do you need the database in hot backup mode at all?  Wouldn't it be the same as losing one side of a mirrored pair?  When that happens, no extra processing is needed. 


Please see the official ORACLE-L FAQ:

Author: Glenn Travis

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