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IBM Cognos 10 Platform => Cognos 10 BI => Cognos Administration => Topic started by: ricky_ru on 08 Oct 2013 04:32:24 AM

Title: Will CS database down result in CM switching
Post by: ricky_ru on 08 Oct 2013 04:32:24 AM
Dears,

We have several cognos instances running. We have 1 active CM(CM01) connects to database 1. And we also have standby CM(CM02) connects to database 1. Database 1 and 2 share the same database files/disk.

My question is if database 1 is down, will the active CM(CM01) be in a bad state immediately and the standby CM(CM02) will take over. Then the active CM (CM01) will be in standy state.

I think the answer is NO. The switching will not happen. Database instance going down does not mean the related CM fails. In this scenario, the standby CM will not take over. As a result, the active CM will report connection errors. Right?

Regards,
Ricky
Title: Re: Will CS database down result in CM switching
Post by: prikala on 08 Oct 2013 04:39:51 AM
My guess is (actually I almost remember this from an actual environment) that what will happen is (in this order):
- Database fails
-  CM1 fails
- CM2 takes over
- CM2 fails
- CM1 and CM2 try to elect an active content manager
- both CM1 and CM2 give up
=> cognos needs restart


Title: Re: Will CS database down result in CM switching
Post by: Grim on 08 Oct 2013 11:32:12 AM
Quote from: prikala on 08 Oct 2013 04:39:51 AM
My guess is (actually I almost remember this from an actual environment) that what will happen is (in this order):
- Database fails
-  CM1 fails
- CM2 takes over
- CM2 fails
- CM1 and CM2 try to elect an active content manager
- both CM1 and CM2 give up
=> cognos needs restart

What Prikala said...  8)
Title: Re: Will CS database down result in CM switching
Post by: ricky_ru on 09 Oct 2013 09:26:52 PM
I have done a test and what you said is right in version 10.1.1

Not sure if cognos 8.4.1 follows the same order?
Title: Will CS database down result in CM switching
Post by: MFGF on 10 Oct 2013 01:07:42 PM
Quote from: ricky_ru on 09 Oct 2013 09:26:52 PM
I have done a test and what you said is right in version 10.1.1

Not sure if cognos 8.4.1 follows the same order?

Hi dear,

Yes - Cognos 8 works in the same way :-)

MF.


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Title: Re: Will CS database down result in CM switching
Post by: ricky_ru on 10 Oct 2013 08:31:52 PM
good to know that. Thank you~~
Title: Re: Will CS database down result in CM switching
Post by: kommireddy on 21 Oct 2013 03:20:27 PM
I have seen situations where, standby cm assuming primary role and primary going to standby when CS DB goes down for few minutes, also happens if there's any network glitch and db connections gets terminated on CS.