October 12, 2011 at 11:19 pm
Database mirroring is a new form of assuring high availability for mission-critical databases. The mirroring concept is similar to log shipping in that transactions are applied to two copies of the same database. The primary database is referred to as the principal and the standby database is referred to as the mirror. Mirroring supports automatic failover from primary to standby server; database administrator could also perform a manual failover. Mirroring is configured at a database level. If you wish to provide high availability for multiple databases on a given server you must configure mirroring for each database separately; however you cannot mirror system databases master, model, tempdb and msdb. Note that mirroring does not provide any sort of load balancing functionality; only one database (principal) is available to users at any given time. The mirror database must reside on a different instance of SQL Server 2005 and is not available for read or write operations. It is possible however to create a snapshot based on a mirror database; database snapshot could be used for read-only queries. It is also possible to have the same physical server host principal and mirror databases on two separate SQL Server instances. However, normally you are likely to host principal and mirror databases on different servers to provide protection against hardware failure.
October 13, 2011 at 10:13 am
sharath chary (10/12/2011)
Database mirroring is a new form of assuring high availability for mission-critical databases. The mirroring concept is similar to log shipping in that transactions are applied to two copies of the same database. The primary database is referred to as the principal and the standby database is referred to as the mirror. Mirroring supports automatic failover from primary to standby server; database administrator could also perform a manual failover. Mirroring is configured at a database level. If you wish to provide high availability for multiple databases on a given server you must configure mirroring for each database separately; however you cannot mirror system databases master, model, tempdb and msdb. Note that mirroring does not provide any sort of load balancing functionality; only one database (principal) is available to users at any given time. The mirror database must reside on a different instance of SQL Server 2005 and is not available for read or write operations. It is possible however to create a snapshot based on a mirror database; database snapshot could be used for read-only queries. It is also possible to have the same physical server host principal and mirror databases on two separate SQL Server instances. However, normally you are likely to host principal and mirror databases on different servers to provide protection against hardware failure.
Yes. So?
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