Availability Group Cluster Type

Cluster type

The possible cluster types depend on the SQL Server version and operating system. Choose one from the following list:

• Windows Server Failover Clustering
• Use when the availability group is hosted on instances of SQL Server that belong to a Windows Server failover cluster for high availability and disaster recovery. Applies to all supported versions of SQL Server.
• EXTERNALUse when the availability group is hosted on an instance of SQL Server that is managed by an external cluster technology for high availability and disaster recovery, for example Pacemaker on Linux. Applies to SQL Server 2017 (14.x) and later.
• NONEUse when the availability group is hosted on an instance of SQL Server that is not managed by a cluster technology for read scale and load balancing. Applies to SQL Server 2017 (14.x) and later.

Database level health detection Check this box to enable database level health detection (DB_FAILOVER) option for the availability group. The database health detection notices when a database is no longer in the online status, when something goes wrong and will trigger the automatic failover of the availability group. See SQL Server Always On Database Health Detection Failover Option.

Sources:

https://docs.microsoft.com/en-us/sql/database-engine/availability-groups/windows/specify-availability-group-name-page?view=sql-server-ver15