In a vSphere High Availability (HA) cluster, what condition can datastore heartbeating detect?

Datastore heartbeating is a feature in vSphere High Availability (HA) that helps to detect certain conditions affecting the availability of virtual machines. Specifically, it is designed to detect network isolation. When a host is isolated from the rest of the network but remains connected to the datastore, datastore heartbeating allows the HA cluster to determine that the host is still functioning and can communicate with the datastore, even if it cannot directly communicate with other hosts or the network services.

This is essential for ensuring that the cluster can properly manage failover in scenarios where a host loses network connectivity but may still be operational. By leveraging the datastore heartbeats, HA ensures that it does not prematurely restart VMs that are effectively still running on the isolated host.

In scenarios like VM disk failure or Fault Tolerance VM failover, these situations would not be directly tied to network isolation and would require other forms of monitoring or detection. The Datastore All Paths Down (APD) event is related to the inability to access storage paths but again does not pertain directly to the network isolation detection capabilities of datastore heartbeating. Thus, network isolation is the specific condition that datastore heartbeating can detect, making this the correct answer.