Configuring high availability for BlackBerry Enterprise Service 10 databases
You can use database mirroring to configure high availability for the BlackBerry Enterprise Service 10 databases. Database mirroring is a Microsoft SQL Server feature that allows you to retain database service and data integrity if issues occur with the databases in the BlackBerry Enterprise Service 10 domain. Database mirroring is supported for both the BlackBerry Configuration Database (associated with the BlackBerry Device Service) and the Management Database (associated with the Universal Device Service).
When you configure database mirroring, you set up a principal database and a mirror database. The databases are hosted on different computers and in different instances of Microsoft SQL Server. After you install the principal database on the principal server, you back up the principal database and use the backup files to create the mirror database on a different computer (the mirror server). You then configure a mirroring relationship between the two databases. When a mirroring session is active, the mirror database performs the same actions and stores the same data as the principal database.
You must configure the databases to use high-safety mode with automatic failover. In high-safety mode, the databases run synchronously. The mirror database synchronizes with the principal database as quickly as possible, and when the databases are synchronized, any changes are committed on both databases.
To enable automatic failover, you set up a witness server to monitor the principal server. If the principal database stops responding, the witness initiates automatic failover to the mirror database. The BlackBerry Enterprise Service 10 components connect to the mirror database, and device service continues without interruption. A role switch occurs: the mirror database becomes the principal database, and the database that was previously the principal is now the mirror database. Role switching can occur several times over the course of a mirroring session.
To learn more about database mirroring, visit technet.microsoft.com/sqlserver to read Database Mirroring - SQL Server 2008 R2 or Database Mirroring - SQL Server 2012.