A vSphere administrator is designing a new cluster for a mission-critical application that requires maximum availability. The cluster will consist of four ESXi hosts. Which vSphere feature should be enabled to protect against host failures while minimizing resource waste?
Trap 1: Enable vSphere DRS and set the migration threshold to the most…
DRS balances workloads across hosts but does not restart VMs after a host failure; that is vSphere HA's function. It tempts because aggressive migration thresholds tune placement responsiveness, yet without HA enabled no failover occurs, and the aggressive setting also increases migration churn rather than protecting availability.
Trap 2: Enable vSphere Fault Tolerance on all VMs in the cluster.
Fault Tolerance maintains a live shadow copy per protected VM, consuming a full host's resources for each pair, so four hosts cannot protect many VMs without waste. It tempts for maximum availability, but the requirement to minimise resource waste points to vSphere HA admission control instead.
Trap 3: Configure vSphere Replication for all VMs to replicate to a…
vSphere Replication provides asynchronous replication to a secondary site for disaster recovery, not host-failure protection within the cluster. It tempts because replication addresses site-level outages, but the scenario concerns host failures in one four-host cluster, where vSphere HA restarts VMs with reserved capacity.
- A
Enable vSphere DRS and set the migration threshold to the most aggressive setting.
Why it fails: DRS balances workloads across hosts but does not restart VMs after a host failure; that is vSphere HA's function. It tempts because aggressive migration thresholds tune placement responsiveness, yet without HA enabled no failover occurs, and the aggressive setting also increases migration churn rather than protecting availability.
- B
Enable vSphere HA and configure admission control to reserve resources for one host failure.
vSphere HA with admission control reserving capacity for one host failure guarantees failover while permitting the remaining three hosts to run the workload, avoiding the full N+1 hardware cost of extra standby hosts. This satisfies maximum availability with minimal resource waste across the four-host cluster.
- C
Enable vSphere Fault Tolerance on all VMs in the cluster.
Why it fails: Fault Tolerance maintains a live shadow copy per protected VM, consuming a full host's resources for each pair, so four hosts cannot protect many VMs without waste. It tempts for maximum availability, but the requirement to minimise resource waste points to vSphere HA admission control instead.
- D
Configure vSphere Replication for all VMs to replicate to a secondary site.
Why it fails: vSphere Replication provides asynchronous replication to a secondary site for disaster recovery, not host-failure protection within the cluster. It tempts because replication addresses site-level outages, but the scenario concerns host failures in one four-host cluster, where vSphere HA restarts VMs with reserved capacity.