Forum Discussion
Installation of SharePoint Server 2016 with HA
On the SharePoint side you're fine. On the SQL side, you should be using SQL AlwaysOn Availability Groups (if using Enterprise) or SQL Clustering (if using Standard). Mirroring is a deprecated technology.
I would not separate the SQL server purposes. Until you have a large enough environment and high enough load to warrant having multiple SQL server instances serving SharePoint content (and even then, try to scale up as much as possible rather than out to reduce management overhead).
I see no mention of a Load Balancer in this mix. In order to provide users with Zero Downtime you must be able to fail over your FrontEnds that are serviing web traffic. In your particual case since your loading this onto App Tier box you should expect your portal sites to remain up but CA will probably be down till patching is complete