One of the most important requirements of business-critical
applications is the availability of the database. Maximizing the
availability of the database is on the top priority list of many
database administrators. Database mirroring, a new feature in Microsoft
SQL Server™ 2005, adds another alternative to the SQL Server
availability arsenal.
To maximize database availability, unplanned as well as planned downtime needs to be minimized. Unplanned downtime is primarily caused by hardware failure (computer failure and storage failure), disk corruption, power outages, communication failures, natural disasters, terrorism, human error, and other factors that cause the primary production database, the production server, and/or the production data center to be unavailable. Planned downtime is primarily due to changes that are applied to the production system. These might be hardware upgrades, software upgrades, and database storage and configuration changes, which cause the primary database or server to be unavailable for a short period of time.
Database mirroring helps minimize both planned and unplanned downtime by:
To maximize database availability, unplanned as well as planned downtime needs to be minimized. Unplanned downtime is primarily caused by hardware failure (computer failure and storage failure), disk corruption, power outages, communication failures, natural disasters, terrorism, human error, and other factors that cause the primary production database, the production server, and/or the production data center to be unavailable. Planned downtime is primarily due to changes that are applied to the production system. These might be hardware upgrades, software upgrades, and database storage and configuration changes, which cause the primary database or server to be unavailable for a short period of time.
Database mirroring helps minimize both planned and unplanned downtime by:
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Maintaining a mirror database that is kept up-to-date with the production database either synchronously or asynchronously.
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Providing ways to perform automatic as well as manual failover.
- Allowing the mirror database to be in a remote data center, thereby providing a foundation for disaster recovery
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