Please allow PI Analysis and PI Notifications to work in an HA setup or in a NLB such as the AF HA recommended scenario. At present the only similar configuration is a failover in a Windows Cluster which TS can't confirm its stability with a NLB pointing to an AF HA. Case #00787942.
ADMIN RESPONSE
Aug 20, 2022
We currently do not have any plans to change HA implementation for PI Analysis Service and PI Notifications Service.
To provide high availability for AF, you need to have a failover solution for the AF Application Service and also the SQL Server backend. In the case of the AF Application Service, our current recommendation is to use a Network Load Balancer. A NLB works for the AF Application Service as the service is stateless and the service is pretty light weight basically passing information between the clients and the SQL Server.
The current recommendation for the backend SQL Server failover is to use SQL Server Always On Availability group.
For PI Analysis Service and PI Notifications Service, the supported configuration for HA is to use Windows Server Failover Cluster. The use of NLB as HA for PI Analysis Service and PI Notifications Service is not supported. For example, in the case of PI Analysis Service, unlike the AF Application Service, it is performing calculations with local data cache and also preserving states. If you were to use a NLB for HA and the NLB switches back-n-forth between multiple services, the system would fail.
