When deploying multiple VMs in a single Availability Set via an ARM template, you want to maximize how many VMs remain available during a host-level (fabric) failure. What value should you set for the platformFaultDomainCount property?

Setting platformFaultDomainCount to its maximum value (which is 3 for most regions) ensures that your VMs are spread across the highest possible number of distinct fault domains within the Availability Set. A fault domain is a physical grouping of hardware that shares a common power source and network switch. By distributing VMs across more fault domains, a failure in one domain (e.g., a power outage or network issue affecting a rack of servers) will impact fewer of your VMs, thus maximizing availability during host-level failures. Choosing a lower value like 10 or 30 would limit this distribution, potentially placing more VMs in fewer fault domains and increasing the risk of simultaneous outages.