cygne17_2 77208 (1/14/2013)
Hi,yes I read this article.
I understand the possible data loss with high-performance mode(asynchronous).
But I still don't understand why we can have possible data loss with high-safety mode?
In high-safety mode, transaction committed on the principal are also committed on the mirror.
Do you have an idea ?
best regards
David
It said it in the article:
If service is forced because the principal server has failed, potential data loss is depends on whether any transaction logs were not sent to the mirror server before the failure. Under high-safety mode, this is possible only until the mirror database becomes synchronized.
There is a possibility if the principal and mirror are synchronized, that when the principal fails that it may not have sent the most recent transactions to the mirror database. These would be transactions that had been queued but not yet sent, perhaps due to network latency or a high volume of transactions. At this point, the databases may have actually been in a synchronizing state but SSMS or Mirroring Monitor had not yet changed to reflect it.