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What is DB Mirroring?
Database mirroring is the process of creating and managing multiple copies of a database for the purpose of database backup, recovery and/or performance optimization.
What is DB mirroring in SQL Server?
Database Mirroring is used to move the database transactions from one SQL Server database (Principal database) to another SQL Server database (Mirror database) on a different instance. In SQL Server Log Shipping and Mirroring can work together to provide solutions for high availability and disaster recovery.
What do you need to know about SQL Server mirroring?
Availability of the operating modes depends on the SQL Server edition. The database that needs to be mirrored must be in the full recovery model. A full database and transaction log backups of the database which will be mirrored must be created and restored on the SQL Server instance which will act as the mirror.
Who is the principal server in database mirroring?
In database mirroring, the partner whose database is currently the principal database. Received transaction log records that are waiting on the disk of a mirror server. The principal server and mirror server perform complementary principal and mirror roles. Optionally, the role of witness is performed by a third server instance.
What happens when Database Mirroring is not synchronized?
When a database mirroring session is synchronized, database mirroring provides a hot standby server that supports rapid failover without a loss of data from committed transactions. When the session is not synchronized, the mirror server is typically available as a warm standby server (with possible data loss).
Can a database be renamed during a mirroring session?
A mirrored database cannot be renamed during a database mirroring session. Database mirroring does not support FILESTREAM. A FILESTREAM filegroup cannot be created on the principal server.