For applications with the highest availability and performance requirements, such as latency-sensitive trading apps, using dedicated failover hosts is the most appropriate HA admission control policy. This policy ensures that specific, reserved hosts are kept in standby, guaranteeing immediate and sufficient resources are available for failover without contention, providing the most predictable recovery performance.

VM-VM affinity rules are used to keep specified virtual machines together on the same host. This is crucial for tightly-coupled applications where VMs frequently communicate with each other, as keeping them on the same host minimizes network latency and improves overall application performance.

Creating multiple smaller datastores and distributing VMs across them is the most effective way to reduce contention in this scenario. A single datastore, even on fast media, can become a bottleneck due to queueing at the datastore level. Distributing the load across multiple datastores (and therefore multiple underlying storage queues/LUNs) parallelizes the I/O flow and significantly reduces latency during peak periods like VDI login storms.

To tolerate the failure of an entire host and restart the VM on the remaining host, the surviving host must have enough unreserved capacity to accommodate the VM’s full resource requirements. Therefore, each host must have at least enough CPU and memory to run the VM itself (8 vCPUs, 64 GB RAM) *plus* host overhead and other VMs. A configuration of 16 cores and 128 GB RAM per host provides the necessary headroom for the failed host’s VM to restart on the other, making it the minimum viable configuration from the options given. A simple 1:1 resource match does not account for failover capacity.

The primary advantage of a dedicated management cluster is resilience and availability. It ensures that the tools needed to manage and recover the environment (like vCenter) remain operational even if the primary workload clusters undergo a full outage, maintenance, or are accidentally misconfigured. This is a foundational design principle for a recoverable and robust SDDC.

Configuring vMotion shares to ‘Low’ and production VM traffic to ‘High’ is the correct approach. NIOC uses a shares-based system to prioritize traffic during contention. Giving production traffic a higher priority ensures that VM network performance is not degraded by vMotion activity. vMotion will still use available bandwidth but will yield to production traffic when the physical uplinks are saturated.

Separate clusters provide complete fault domain isolation. A failure or misconfiguration in one cluster (e.g., a host failure causing HA restarts, or a cluster-wide setting change) cannot directly impact the VMs in the other cluster. Resource pools and folders within a single cluster share the same underlying compute, network, and storage fault domains, and a cluster-level event could affect all VMs.

Creating a VM Override for the specific problematic VMs and setting their DRS automation level to ‘Partially Automated’ is the correct solution. This allows DRS to make automatic placement recommendations (initial placement) but requires manual approval for any migration recommendations. This gives administrators control over when these large, sensitive VMs are moved, preventing disruptive migrations during critical periods.

In a vSAN stretched cluster, the witness component must be placed in a third, separate fault domain (typically a separate physical location). This is critical for maintaining quorum during a network partition or site failure. Placing it in either data site would defeat the purpose, as the witness would be lost if that entire site failed. A dedicated witness appliance in a third location is the standard and required design.

For applications with the highest availability and performance requirements, such as latency-sensitive trading apps, using dedicated failover hosts is the most appropriate HA admission control policy. This policy ensures that specific, reserved hosts are kept in standby, guaranteeing immediate and sufficient resources are available for failover without contention, providing the most predictable recovery performance.0