Fail over Operator
A fail-over operator is a user that is specifically designated to be contacted by the SQL system if other operators are not available for a system failure. SQL provides the means for the system to automatically email or page designated people in case of system issues. These issues can be a failure of the server, a failure of tables being accessed, and other system and processing errors.
The fail-over operator is the person that is contacted if none of the initial operators are contacted or if there is a failure in the systems that alert operators by either pager or email. Failures that involve the lists, processes, and report systems that alert operators use the fail-over operator as the contact. This insures that there is full coverage of alerting and issue reporting for the entire system, including the alert system.
The fail-over operator needs to be a system administrator and have access to root controls for the types of problems that may trigger an alert. Since fail-over alerts may be reporting a problem with the alert system itself, issues will require admin level control and operation.
SQL Server 2012 was the last version to use SQL Server Agent for providing the page and net send options. Since then, SQL Server Management Studio is the recommended system to use and configure the fail-over operation alerts. It is also recommended that any applications that have been developed for the SQL Server Agent be rewritten for SQL Server Management Studio. However, there are also third-party applications that provide these services and configurations that may also allow for an easy transition of a database being upgraded from an older version to current versions of SQL Server.
Using a fail-over operator is something that has to be configured, it is not on by default. There are arguments about whether it is entirely necessary, but there are no disadvantages to using fail-over. Most of the time, admins not using the fail-over operator option have simply not set it up out of ignorance or a belief that is it unnecessary.