There are three operational modes that control when and how transactions are recorded to the mirror server. In almost all cases, the default mode, synchronous, is recommended as it is the most reliable.
Three operational modes are provided for database mirroring:
These modes control when and how transactions are recorded on the mirror server, and you set them by using the SET MIRROR OPTION statement to set the value of the synchronization_mode option.
The sending of log pages to the copy nodes is always done asynchronously, regardless of the mode chosen.
When choosing a synchronization mode for your database mirroring system, you must determine whether the performance of modifications to the primary database or avoiding the loss of transactions is more important when failover occurs.
You can check the database mirroring mode by querying the value of the MirrorMode database property:
SELECT DB_PROPERTY( 'MirrorMode' );
Discuter à propos de cette page dans DocCommentXchange.
|Copyright © 2013, SAP AG ou société affiliée SAP - SAP Sybase SQL Anywhere 16.0|