Re: reinstate database without flashback/DB Restore/RMAN

From: max scalf <>
Date: Mon, 8 Jun 2015 09:47:42 -0500
Message-ID: <>

Hello list,

I have one other question related to this. Let's say if I want to take my primary site down for hardware maintenance, I am assuming I would do a switchover first and then take down old primary. My question is when the original primary comes back up (let's say after 6 hours) and we have a big gap now.

  1. Does it request all the logs from the current primary to make it in sync
  2. how does it deal with let's say I have backed up my archive logs with rman in my now primary so the database do not hang, how do we deal with that?

On Friday, June 5, 2015, Andrew Kerber <> wrote:

> I'm sorry, you are right. The incarnation changes.
> Sent from my iPad
> On Jun 5, 2015, at 7:08 AM, Ram Cheruvattath <
> <javascript:_e(%7B%7D,'cvml','');>> wrote:
> The DBID on a physical standby should not change due to a failover. Have
> you tested this?
> Ram
> *From:* Andrew Kerber
> <javascript:_e(%7B%7D,'cvml','');>
> *Sent:* Thursday, June 04, 2015 3:40 PM
> *To:* max scalf <javascript:_e(%7B%7D,'cvml','');>
> *Cc:* Oracle Mailing List
> <javascript:_e(%7B%7D,'cvml','');>
> *Subject:* Re: reinstate database without flashback/DB Restore/RMAN
> Nope. At that point, if you have a done failover, the dbid on the standby
> is different from the primary. In effect, at that point its a completely
> different database. Flashback allows you to flash the primary back to an
> instant before the divergence, and you can apply the logs from that point,
> but you have to flash it back for that to work.
> On Thu, Jun 4, 2015 at 1:29 PM, max scalf <
> <javascript:_e(%7B%7D,'cvml','');>> wrote:
>> Hello list,
>> I am trying to get my head around reinstating a database in dataguard
>> scenario, i am very new to DG and hence having issue trying to understand
>> this.
>> So lets say i have datacenter DC-A and Datacenter DC-B and i have setup
>> DG between the two(Max Perf mode). Now lets say DC-A goes down
>> unexpectedly (and lets assume that DC-A will come back up in 3-4 hours as
>> know we know whats wrong and network team is trying to fix that), also lets
>> assume this happened at noon and my log seq# at primary was 300. Obviously
>> in the mean time i am going to FAILOVER to standby in DC-B and everything
>> is happy. Time passes along and now its 4PM and lets assume now my primary
>> in DC-B is at log seq# 320.
>> Now at 4PM, my DC-A is back and i want to bring the former primary into
>> standby mode. I can either use flashback(if enabled earlier) or recreate
>> my standby again to do that. My question is, instead of using flashback or
>> rman to recreate my standby(DC-A), cant i just mount my database in DC-A,
>> copy over logs from seq# 300-320 from DC-B on to DC-A, roll forward DC-A
>> and then start my redo apply instead of recreating standby(or using
>> flashback)??
>> I guess in short i am asking y do we have to use flashback or use
>> RMAN/re-create to reinstate my standby database? is there any other way to
>> reinstate my database(fromer primary).
> --
> Andrew W. Kerber
> 'If at first you dont succeed, dont take up skydiving.'

Received on Mon Jun 08 2015 - 16:47:42 CEST

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