Re: reinstate database without flashback/DB Restore/RMAN

From: Andrew Kerber <andrew.kerber_at_gmail.com>
Date: Thu, 4 Jun 2015 16:25:33 -0500
Message-ID: <CAJvnOJawhCXEL-EAz2+36srcwwLh0UVXzqKkbC2Fa6UiQPg4Pg_at_mail.gmail.com>

When you fail over you have to open resetlogs. Switchover is a clean switch, no resetlogs required.

On Thu, Jun 4, 2015 at 4:23 PM, max scalf <oracle.blog3_at_gmail.com> wrote:

> okay make sense, one question when we FAILOVER why does the DBID changes
> ?? or is it also doing a resetlogs ?
>
> On Thu, Jun 4, 2015 at 3:16 PM, Andrew Kerber <andrew.kerber_at_gmail.com>
> wrote:
>
>> I am referring to the original primary in that case. As I understand it,
>> with flashback turned on, the reinstate command in dgmgrl will flash the
>> original primary back to an earlier point, then apply the logs from the
>> current primary to put the original primary into standby mode, ready for a
>> clean switchover.
>>
>> On Thu, Jun 4, 2015 at 2:57 PM, max scalf <oracle.blog3_at_gmail.com> wrote:
>>
>>> Thanks Andrew, i did not realized that. Also looks like the log seq#
>>> resets back to 1 on the new primary(DC-B).
>>>
>>> Also when you mentioned "flashback allows you to flash the PRIMARY back
>>> to an instance before the divergence and start the apply"...are you talking
>>> in this situation the CURRENT PRIMARY (DC-B) which has been up for 4 hours
>>> now will be flashed back to noon followed by rollforward ?? Wouldnt that
>>> be on the standby ??
>>>
>>> On Thu, Jun 4, 2015 at 2:40 PM, Andrew Kerber <andrew.kerber_at_gmail.com>
>>> wrote:
>>>
>>>> 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 <oracle.blog3_at_gmail.com>
>>>> 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.'
>>>>
>>>
>>>
>>
>>
>> --
>> Andrew W. Kerber
>>
>> 'If at first you dont succeed, dont take up skydiving.'
>>
>
>

-- 
Andrew W. Kerber

'If at first you dont succeed, dont take up skydiving.'

--
http://www.freelists.org/webpage/oracle-l

Received on Thu Jun 04 2015 - 23:25:33 CEST