For your information:
• When you have a SQL cluster for failover and the actual failover happens, the AOS will lose the connection to the SQL server and you have to restart the AOS service.
• When you have an AOS cluster and you set it to start "On demand", it will not work. If the AOS instances are not running they will never start when clients try to connect. Sad but true. Maybe this will change when we get the new Dynamics Ax 4.0.