Active Standby Failover

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Active Standby Failover

Postby sivakumarocp » Mon Dec 16, 2013 3:32 pm

Hi Tim,

We have production DB for that we have Active Standby Database (ADG instance) configured.
Application team is going to perform Upgrade from their end. and if something goes wrong we are planning to activate the ADG Instance inorder or reduce donwtime.

I would like to know how to Activate ADG Instance.

is it possible?
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Re: Active Standby Failover

Postby Tim... » Mon Dec 16, 2013 8:15 pm

Hi.

Well, a couple of things to consider...

1) You have to plan what you are going to do to the standby before you start the upgrade. You've got to make sure changes are not shipped to the standby during the upgrade you would are going to mess things up. You effectively need to split standby off before starting the upgrade on the primary, or all the DDL and DML will be shipped to the standby.

2) You activate a ADG standby the same way you do any other.

http://www.oracle-base.com/articles/11g ... p#failover

You will need to check the upgrade guide to check the suggested approach and the data guard manual.

Personally, I would not do what you are planning. I would use flashback database on the primary to flashback to a PIT before the backup started in the event of a problem.

Cheers

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Re: Active Standby Failover

Postby sivakumarocp » Tue Dec 17, 2013 1:26 am

Hi Tim,

There problem here is, in our Production DB we have not enabled Flashback feature.
so that's the reason why I am planing for this method.

yes ofcourse, Before to being the upgrade activity I will cut the link between the Primary DB and the ADG instance. so If something goes wrong i'll enable our ADG instance (which is now copy of our Prod DB) and I'll make it as Primary then release it to User.

I thought this method would be a quickest way to release the DB to the end user with out any issue.

Expecting your thoughts here.

or else is there any other way to achieve this.
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Re: Active Standby Failover

Postby Tim... » Tue Dec 17, 2013 8:06 am

Hi.

That's fine. :)

Cheers

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Re: Active Standby Failover

Postby sivakumarocp » Tue Dec 17, 2013 1:42 pm

Hi Tim,

When I check the switchover status on my ADG instance it shows as NOT ALLOWED.

SQL> SELECT SWITCHOVER_STATUS FROM V$DATABASE;

SWITCHOVER_STATUS
--------------------
NOT ALLOWED

In this case, will I be able to perform the failover.
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Re: Active Standby Failover

Postby Tim... » Tue Dec 17, 2013 2:19 pm

Hi.

And the manual says,

"NOT ALLOWED - Either this is a standby database and the primary database has not been switched first or this is a primary database and there are no standby databases."


A switchover is a controlled event. You can not switch the standby until you have initiated the process in the primary database. This status is accurate for your system as you've not initiated a switchover on your primary.

Remember, failover and switchover are not the same thing. :)

Cheers

Tim...
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