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 Transaction Safety?

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sachinsamuel
Constraint Violating Yak Guru

383 Posts

Posted - 2007-11-28 : 06:28:00
Hi All,

We are evaluating DB mirroring for our production box. But we have some queries with the operating mode available for mirroring.

1) I set the database mirroring operation mode to full safety mode which is with synchronous. And Then executed a command to insert data in bulk in principal, the changes were committed to principal even when they are still getting mirrored to mirror server.

But as per the mirroring documentation from Microsoft says this

"If transaction safety (or just 'safety') is set to FULL, the principal and mirror servers operate in a synchronous transfer mode. As the principal server hardens its principal database log records to disk, it also sends them to the mirror. The principal then waits for a response from the mirror server. The mirror responds when it has hardened those same log records to the mirror's log disk."

Is this a bug or I am doing anything wrong.


2) Mirroring documentation also says that when the transaction is on full safety mode, and if mirror and witness goes down then principal goes to read only mode. But again I saw deviation from the documentation because when I turned mirror and witness off, principal went to "In recovery" mode.


Please help incase anybody have faced this before or can help me if I am interpreting it wrong.

Thanks
Sachin


Don't sit back because of failure. It will come back to check if you still available. -- Binu

suresha_b
Yak Posting Veteran

82 Posts

Posted - 2007-11-28 : 07:17:48
How did you check that "changes were committed to principal even when they are still getting mirrored to mirror server.
"? When the mirror database is in "Restoring..." status, you can't read it.

Did you create snapshot database of the mirror database?

Suresh B.
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sachinsamuel
Constraint Violating Yak Guru

383 Posts

Posted - 2007-11-28 : 07:44:27

You can launch database mirroring monitor which will show the amount of pending logs which are pending to be applied. You can also see unsent log to the mirror.

Regards,
Sachin


Don't sit back because of failure. It will come back to check if you still available. -- Binu
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rmiao
Master Smack Fu Yak Hacker

7266 Posts

Posted - 2007-11-29 : 02:22:58
Should report those to Microsoft.
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