SQL Server 2008 Administration in Action

11.7. Best practice considerations: high availability

As with performance tuning where there will always be a bottleneck somewhere, each high-availability plan typically has its own weak points. On its own, database mirroring won't protect against poor maintenance practices and corrupted backups; it should therefore be seen as one component of a much broader high-availability plan.

• Service level agreements should be considered your binding contract. You wouldn't pay a builder to build your house without specific instructions and contract conditions; likewise, you can't effectively design and administer a highly available database system without a set of service level agreements in place. Know what they are and have confidence that they're achievable ...