This documentation provides essential information on SQL Server High Availability features.
High Availability (HA) in SQL Server ensures that your database remains available even in the event of a failure. It involves redundancy, replication, and automatic failover mechanisms.
SQL Server HA utilizes multiple instances of the database. These instances are mirrored – a copy of the data resides in a separate, geographically distributed location.
SQL Server HA uses replication to keep the database state consistent. It utilizes synchronous replication for data consistency, and asynchronous replication for faster failover.
When a failure occurs, SQL Server HA automatically switches over to a healthy instance. The database state is synchronized between the primary instance and the standby instance.
Ensuring data consistency is paramount in HA. SQL Server HA employs techniques like timestamp synchronization to minimize data discrepancies during failover.
– Primary Instance: The main database instance. – Standby Instance: A replica of the primary instance. – Failover: The automatic switching of a database instance to a standby.
– Secondary Instance: The standby database instance. – Replication Tag: Allows you to monitor replication status. – Failover Cluster