October 29, 2011 at 9:04 pm
With DB Mirroring, do transactions get applied to the mirror first then the principle? Or is it the other way around?
Thanks
October 30, 2011 at 4:18 am
smallmoney (10/29/2011)
With DB Mirroring, do transactions get applied to the mirror first then the principle? Or is it the other way around?Thanks
If mirroring is in asynchronous mode, transactions are committed to principle and sent to mirror.
In synchronous mode, the transaction is hardened on principle as well as mirror. Once mirror sends acknowledgement, the transaction is considered to be successful.
October 31, 2011 at 12:42 am
In Mirroring there are 3 modes
1)Asynchronous mode--When you select Asynchronous mode changes 1st commit at principal then transferred to mirror where there is chances of data loss.
2)Synchronous mode(with Automatic Failover)When you select Synchronous mode with Automatic Failover you need a witness server along with Principal & mirror server.The changes 1st commit at mirror than it commits at Principal.
3)Synchronous mode(without Automatic Failover)When you select Synchronous mode without automatic failover you do not need a witness server but incase of failure you have to manually failover. In this case also changes 1st commit at mirror than it commits at Principal
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